Drive and dosing device with a stop element for preventing the setting of a dose

ABSTRACT

Drive and dosing devices for injection devices are disclosed. An embodiment may include a threaded piston rod moveable in a dispensing direction for dispensing a product. A rotation member may be operatively connected to a stop limiter and threadably engaged with the piston rod. Rotation of the rotation member may cause the piston rod to move in the dispensing direction. An embodiment may include a dose knob rotatable for changing a dose. The device may further include a stop element threadably engaged with the piston rod and having a catch. The dose knob may be coupled with the stop element such that during increase of a dose, the stop element is screwed toward the distal end of the piston rod and the catch is moved towards the stop limiter. The stop element prevents increasing a dose when the catch abuts the stop limiter.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Patent ApplicationNo. PCT/CH2014/000090 filed Jul. 1, 2014, which claims priority toEuropean Patent Application No. 13177387.1 filed Jul. 22, 2013, theentire contents of each are incorporated herein by reference for any andall purposes.

BACKGROUND

Disclosed embodiments relate to drive and dosing devices for aninjection device having a mechanism for preventing the setting of a dosewhich exceeds the amount of product present in a cartridge. The driveand dosing device serves the purpose of dispensing a fluid product,particularly a medicament.

The term “medicament” includes any flowable medical formulation suitablefor controlled administration though, for example, a cannula or a hollowneedle and comprises a liquid, a solution, a gel or a fine suspensioncontaining one or more medical active ingredients. A medicament can be acomposition comprising a single active ingredient or a pre-mixed orco-formulated composition with more than one active ingredient presentin a single container. Medication includes drugs such as peptides (e.g.,insulin, insulin-containing drugs, GLP-1 containing drugs or derived oranalogous preparations), proteins and hormones, active ingredientsderived from—or harvested by—biological sources, active ingredientsbased on hormones or genes, nutritional formulations, enzymes and othersubstances in both solid (suspended) or liquid form but alsopolysaccharides, vaccines, DNA, RNA, oligonucleotides, antibodies orparts of antibodies but also appropriate basic, auxiliary and carriersubstances.

Injection devices such as injection pens are known from the state of theart. Individual doses of a product can be set and subsequently dispensedwith such injection devices. This procedure can be repeated severaltimes. Because the amount of medicament present in the cartridge islimited, namely often 300 International Units (IU), a dose may be setabove the amount that can be dispensed from the cartridge, particularlythe nominal volume, which is also called the in the cartridge containedvolume. This could result in, for example, 35 IU being set while only 20IU can be dispensed with a subsequent injection. The difference of 15 IUis missing in the medication. A user of the device might not notice thiswhich can lead to hazardous adverse dosing.

From the state of the art other dosing devices are proposed whichprevent setting a dose which exceeds the amount of product present inthe cartridge. For example, in FIG. 3 of WO 2001/019434, a device isproposed having a drive sleeve surrounding a piston rod having at itsouter surface a thread engaging an inner thread of a stop nut. The stopnut has a recess and a sleeve surrounding the stop nut such that thestop nut is in a rotational secure and axially slidable engagement withthe sleeve. If the outer sleeve is rotated relative to the drive sleeve,which happens during dose setting, then the stop nut co-rotates andscrews itself along the thread of the drive sleeve towards a stopposition. During dose delivery, the stop nut stands still with respectto the drive sleeve and the outer sleeve thus building a countingmechanism counting the set and dispensed doses. At the attempt ofsetting a dose which exceeds the amount of product present in thecartridge, the stop nut abuts a catch on the drive sleeve and blocks afurther increase of dose setting such that the setting of a doseexceeding the amount present in the cartridge is prevented.

An alternative example device with an identical effect is shown in WO2007/017052. Amongst other features, a stop nut is described that is ina threaded engagement with an outer thread present at a piston rod. Thepiston rod is rotatable with respect to the housing for dispensing a setdose and is also in a threaded engagement with the housing such that arotation of the piston rod causes the piston rod to move in thedispensing direction. During setting of a dose which would exceed theamount of product present in the cartridge, the stop nut hits amechanical stop present at the proximal end of the piston rod wherebythe mechanism is blocked, and the setting of a dose exceeding the amountpresent in the cartridge is prevented.

In WO 2005/018721, an injection device is described having a dose knobthat can be rotated relative to a housing for setting a dose and thatrotation is transmitted to a dose setting member or scale drum. Duringdispensing, the dose knob is rotationally decoupled from the scale drum.Thus, during dose delivery the knob is pressed with the thumb and thisknob does not rotate relative to the housing versus the scale drum thatrotates back into the device.

In WO 2004/020027 an injection device is described having a dose knobfor setting a dose and an overload protection for the dose settingmechanics. For example, if a user wants to over-torque the dose knobwhen the rotation is in principle blocked by the dose setting mechanics,thus preventing damage to the mechanical components of the system.

SUMMARY

Disclosed embodiments may provide an alternative drive and dosing devicefor an injection device compared to the above mentioned mechanisms.Embodiments may also provide a drive and dosing mechanism with improveddrive efficiency and improved device handling for the user. Embodimentsmay reduce the size and complexity of the device.

These objects are solved with, for example, a drive and dosing deviceaccording to claim 1. Preferred embodiments are specified in thedependent claims, the description and the figures.

In an example, the drive and dosing device has a housing, such as asingle-part or multi-part housing. The housing can, for example, have anelongated shape. The housing can have, for example, a sleeve shape orexhibit one or more sleeves which, for example, can be concentricallyarranged. The housing can have an outer sleeve which can be held by theuser of the device.

The housing can, for example, have an inner sleeve, often called themechanics holder, which is rotationally and preferably axially connectedto the outer sleeve, such as through a snap-fit mechanism or a glue orwelding connection. The housing can, for example, have a display, suchas a viewing window for reading the current dose setting. The viewingwindow can, for example, be made from a transparent material, such as alens. The viewing window may be defined by only a cut-out in thehousing.

A sleeve shaped cartridge holder is or can be removable or permanentlyattached to the distal end of the housing. A cartridge (e.g., anampoule) is held or can be held by the cartridge holder.

The device also encompasses a piston rod with a distal end, a proximalend and a thread, preferably an outer thread and which can be moved withrespect to the housing towards the dispensing direction. The thread islocated between the distal end and the proximal end. At the distal endof the piston rod can be arranged, for example, a saucer-shaped flangethat pushes against, and can move a plug present in the cartridge thatis attached or can be attached to the drive and dosing device. Thepiston rod is, with respect to the housing, preferably moveable in thedispensing direction and rotationally fixed. The piston rod can berotationally secured by the housing or by a guiding member that isrotationally secure connected to the housing. The guiding member can berotationally secured with respect to the housing, whereby the piston rodis also rotationally-secure with respect to and mounted to the guidingmember. Preferably, the piston rod is axially (e.g., along thelongitudinal axis of the device) slidable relative to the guidingmember. The piston rod can, for example, have a non-circular crosssection. In particular, the piston rod can have one or more notches(e.g., two) or flattened surfaces that extend along the longitudinalaxis of the piston rod and engage the guiding member such that thepiston rod is axially slidable and rotationally locked. The guidingmember can be, for example, axially locked and slidable with respect tothe housing. The guiding member can be a part of the housing or is aseparate part, particularly when the guiding member is axially moveablealong the longitudinal axis and relative to the housing. If the guidingmember is rotationally and axially secured with respect to the housing,then, in particular, it can be considered to be part of the housing.

Furthermore, the drive and dosing device has a rotation member whichengages the thread of the piston rod and which is operatively,particularly torque-proof connected with a stop limiter. A rotation ofthe rotation member relative to the piston rod ensures that the pistonrod moves relative to the housing in the dispensing direction along thelongitudinal axis of the device. The rotation member can, with respectto the housing be axially locked or only restricted axially moveable.The piston rod is screwed in the distal direction by rotation of therotating member with respect to the housing. In particular, there may bea screw type of motion between the rotation member and the piston rod,and the piston rod is guided by the housing or the guiding member suchthat the piston rod axially slides in the dispensing direction (e.g.,along a dispensing distance), and is, for example, rotationally lockedwith respect to the housing.

Further, a dose setting member is provided that is rotatable in a firstrotation direction versus the housing and/or piston rod for increasing adose that can be dispensed from the cartridge. The dose setting membercan, in particular during the dose setting and dispensing, be axiallylocked with respect to the housing. However, preferably, the dosesetting member is screwable with respect to the housing such that thedose setting member can be rotated out of the housing by a rotation inthe first direction and can be rotated back into the housing by arotation in the opposite direction (e.g., the second direction).Preferably, the dose setting member is arranged at the proximal end ofthe housing and can be rotated out of the proximal end of the housingand can be rotated into the proximal end of the housing. Preferably, thedose setting member can be rotated into the housing or at least in thesecond rotation direction for decreasing a dose that can be dispensedand/or dispensing a dose. A dose correction or reduction of a dose canbe done by rotation of the dose setting member in the second rotationdirection. Preferably, the dose setting member can be held by the userof the device and can be rotated relative to the housing. The dosesetting member can also be designated as a dose knob.

The drive and dosing device further comprises a stop element which has athread engaging a further thread of the piston rod or the threadengaging the rotation member. The dose knob is connected with the stopelement such that a rotation of the dose knob relative to the piston rodand/or housing in the first direction results in a rotation of the stopelement relative to the piston rod, preferably in the same direction asfor the dose knob. The stop element can be screwed towards the distalend of the piston rod by rotation of the dose knob and/or the stopelement, particularly in the first rotation direction. The stop elementhas a catch which through rotation of the dose knob in the firstdirection moves towards the stop limiter or a stop position. Thedistance between the stop limiter and the catch, measured along ahelix-shaped curve corresponding to the thread engaging the stopelement, is proportional to the volume, particularly either the nominalvolume or the dispensable volume in the cartridge. This distance isreduced by rotation of the dose knob in the first direction. If thecatch abuts the stop limiter, then the stop element blocks the settingof a dose, for example, which would exceed the amount of product presentin the cartridge or—in other words—blocks the rotation of the of thedose knob in the first direction. Thereby the setting of a dose isprevented which would exceed the amount of product present in thecartridge (e.g. the nominal volume). Further, when a higher dose couldbe set with the drive and dosing device, a value of the dose scale canbe read in the viewing window that is below the maximum value of thedose scale. Alternatively the setting of a dose can be prevented whichwould result in less than the residual volume of the nominal volumeremaining in the cartridge or that dispensing would result in dispensingat least a part of the residual volume, particularly if with the driveand dosing device in principle a higher dose could be set, respectively,when in the viewing window a value of the dose scale can be read whichis below the maximum value of the dose scale. In particular, a furtheraspect described below is referenced. The set dose or thein-the-cartridge-available-dispensable dose can be read from the scaledrum via the viewing window. Thereby, the user is reliably notifiedwhich dose he can safely administer to himself with the device.

An extremely stable mechanism is achieved by the stop element abuttingthe stop limiter which is rotationally secured with the rotation member.This is because the parts of rotation member, piston rod and stopelement are locked with respect to each other when the catch abuts thestop limiter (e.g., when the stop element is in its stop position).

More preferably, the rotation member features the stop limiter. Therotation member can be single part or multi-part. If the rotation memberis multi-part, then it is preferred that the parts forming the rotationmember are tightly connected to each other and/or behave as a singlepart. The advantage of a multi-part rotation member is that one part canbe made from a first polymer and the other part can be made from asecond polymer which is different from the first polymer (e.g., itpossesses other properties). For example, the part which is in athreaded engagement with the piston rod can have optimized frictionalproperties (e.g., building a low friction bearing couple with the pistonrod). The other part which, for example, can feature the stop limiter,can be optimized with respect to mechanical strength (e.g., it is madefrom a fiber reinforced polymer). The latter part can, for example,exhibit one or more coupling structures like, for example a tooth systemor teeth (e.g., toothing). In particular for the coupling structures itis advantageous to keep an eye on an increased mechanical strength.

In preferred embodiments, the dose knob is rotatable in the seconddirection, which is opposite to the first rotation direction, fordecreasing the set dose. The rotation of the dose knob relative to thepiston rod in the second rotation direction can result in a rotation ofthe stop element relative to the piston rod, preferably also in thesecond rotation direction. As a result of this rotation, the stopelement can be screwed towards the proximal end of the piston rod.Thereby, the stop element is preferably also moved along thelongitudinal axis of the housing. Particularly, by the rotation of thedose knob and/or stop element relative to the piston rod it is achievedthat the catch moves away from the stop limiter (e.g., the distancebetween the catch and the stop limiter increases).

The drive and dosing device comprises an actuation member, which isactuated (preferably pushed) by a user of the device for the dispensingof a set dose. The actuation member is preferably located at theproximal end of the drive and dosing device. Particularly duringactuation, the actuation member can be moved along the longitudinal axisand/or in the distal direction. The actuation member can be held by thedose knob. As an example, the actuation member can be the proximal endof the drive and dosing device. The actuation member can be particularlyshaped as the dose button. The actuation member is advantageouslylocated such that the user of the device can actuate (preferably push)the actuation member with the thumb of the hand holding the drive anddosing device. The actuation member can be pushed relative to thehousing and/or dose knob into the distal direction from a non-actuatedposition in an actuated position. Preferably there is a spring which isstressed during actuation of the actuation member. If the actuationmember is released, then the actuation member can move from the actuatedposition into the non-actuated position, preferably through thepre-stressed spring.

In embodiments whereby the dose knob is rotated out of the proximal endof the housing for increasing a dose, it is preferred that pushing theactuation member at first initiates a distal movement of the actuationmember relative to the dose knob (actuation distance of the actuationmember), whereby a further pushing of the actuation member causes thedose knob to screw back into the housing (e.g., by the dose settingdistance of the dose knob).

Pressing the actuation member over the dose setting distance by a userensures that the rotation member is rotated with respect to the housingand piston rod (preferably in the second direction), whereby the pistonrod moves relative to the housing in the dispensing direction. The stopelement is screwed at the same time towards the proximal end of thepiston rod whereby the distance between the stop limiter and the catchideally remains constant. The described effects are the result of thedose knob that screws back into the housing whereby the rotation memberrotates relative to the housing and the piston rod, particularly, in thesecond direction. During this movement (e.g., during dispensing) thestop element is axially immovable with respect to the housing androtates in the second rotation direction. Thereby it is achieved, thatthe distance between the stop limiter and the catch remains constant,but the stop element screws in the proximal direction with respect tothe piston rod because the piston rod does not perform a rotationalmovement during the dose dispensing and instead performs an axialmovement.

In the above described embodiment, the actuation member (or dose button)and dose setting member (or dose knob) are designed as two separateparts and actuation of the dose button by the user of the device andfurther pushing of the dose button ensures that the dose setting memberis rotated back into the proximal end of the housing. The user grips thehousing in his hand and pushes with his thumb the dose button togetherwith the dose knob back into the housing. Thereby the dose knobpreferably rotates in the second direction whereas the dose button isrotationally secured by the thumb of the user. The rotation of the twoparts versus each other during dose dispensing might be impaired by theuser's thumb pushing the non-rotating dose button and also touching therotating dose knob. Therefore the device may be designed such that thefunctionalities of the dose button for dose dispensing and the dose knobfor dose setting are combined as a single part for the user. Forexample, during dose setting the user rotates the combined button forsetting a dose and during dose delivery he or she pushes the combinedbutton for dispensing the set dose and the combined button does notrotate during dispensing. Thus the two functionalities of dose settingand dose delivery can be activated by two separate parts or one singlepart. Such a combined dose setting and dose delivery button is knownfrom the art (see, e.g., Eli Lilly's Kwikpen; see also WO 2005/018721).

As mentioned above, the driving mechanism has a stop element whichprevents setting a dose which would exceed the amount of product presentin the cartridge when the stop element is in the stop position (e.g.,when the catch of the stop element abuts the stop limiter). In thatsituation, a user cannot set a higher dose by rotating the dose knob inthe first rotation direction and the torque is transmitted from the doseknob via the catch to the stop limiter. To prevent over-torqueing of thedrive and dosing mechanism which could damage the assembly of stoplimiter, catch, stop element or other drive components of the mechanism,it can be advantageous to provide a unidirectional overload protectionmechanism between the dose setting mechanism and the drive mechanism.Such an overload protection can be designed, for example as an overloadclutch, as a unidirectional ratchet system, a predetermined breakingpoint or any other coupling system having an upper torque limit beforedecoupling the coupling. In case the users attempts to rotate the doseknob in the first rotation direction when the stop element is in thestop position, the overload protection is activated before the parts ofthe drive mechanism are mechanically damaged. Alternatively oradditionally, such an overload protection can protect the drivemechanism or stop limiting the setting of each individual dose (e.g.,the stop zero dose and/or the stop maximum dose). In that case abidirectional overload protection may be used. The overload protectionmechanism is located between the dose knob and the rotation member, forexample between the dose knob and an intermediate sleeve such as, forexample, the drive sleeve, dose sleeve or coupling sleeve (describedbelow), preferably between the dose knob and the scale drum. Asmentioned above, the dose knob and dose button can be designed as twoseparate parts of as one single part. In the case the dose knob and dosebutton are constructed as two separate parts, then the overloadprotection mechanism can also be located between the dose knob and thedose button. The overload protection can be a reversible or anirreversible system and the activation of the system can be notified tothe user by an audible, tactile or visible indicator. Thereby the useris notified that he or she uses excessive torque on the system, while atthe same time protecting the drive mechanism by only allowing a presetthreshold torque value to be transmitted to the drive and dosingmechanism. As mentioned before, the Eli Lilly Kwikpen (see, e.g., WO2005/018721) already has the feature of a combined dose setting/deliverybutton but does not have the overload protection mechanism for the dosesetting member. An overload protection has been disclosed in WO2004/020027 but this publication does not disclose the overloadprotection in combination with a combined dose knob. In WO 2004/020027an overload protection is disclosed to protect the dose settingmechanics from overloading but lacks the feature of the combined doseknob of the present embodiments. Disclosed embodiments minimize thenumber of parts (and therefore the cost) and/or complexity of the deviceby combining the overload protection and the combined dose knob in asingle part, an overload clutch. Thus the overload protection of anembodiment is active when the dose knob is in the non-actuated positionand the overload protection is non-active when the dose knob is in theactuated position.

A drive and dosing mechanism is described for a reusable or disposableinjection device comprising a tubular housing, a piston rod having athread and which is moveable in a dispensing direction with respect tothe housing for dispensing a product, a rotation member, a scale drumand a dose knob. The rotation member can be engaged with the thread ofthe piston rod whereby a rotation of the rotation member in the seconddirection relative to the piston rod ensures that the piston is movedrelative to the housing in the dispensing direction. The scale drumhaving a helical shaped dose scale on its surface and the housing has aregion for viewing the dose scale, particularly a viewing window, forreading the value of the dose scale corresponding to the set dose. Thedose knob present at the proximal end of the housing can be rotatedduring dose setting in a first direction or in a second direction whichis opposite to the first direction, whereby during dose setting, whenthe dose knob is not actuated, the dose knob is rotationally coupled tothe scale drum and a rotation of the dose knob is transferred to thescale drum which performs a screw type of movement relative to thehousing such that the helical shaped dose scale moves along the viewingwindow. The dose knob is actuated during dose delivery, and the doseknob is rotationally decoupled from the scale drum, and the dose knoband scale drum move together in the distal direction, and the scale drumrotates in the second direction without a rotation of the dose knob,whereby the rotation of the scale drum in the second direction istransferred to the rotation member and the piston rod is moved in thedispensing direction for dispensing the product from the cartridge.

The dose knob is moved in the distal direction with respect to the scaledrum without rotation during actuation of the dose knob. The scale drumdoes not move in the distal direction or rotate with respect to thehousing during actuation of the dose knob. A sleeve shaped overloadclutch can be present between the dose knob and the scale drum, theoverload clutch being connected to the scale drum and the dose knobbeing axially slidable with respect to the overload clutch. The overloadclutch can have a coupling structure, preferably teeth,circumferentially arranged on the outside surface which can engage acircumferentially arranged coupling structure, preferably teeth presentat the inside of the dose knob. The two coupling structures are arrangedsuch that they can slide versus each other along the longitudinal axisof the drive and dosing mechanism. The two coupling structures beingcoupled when the dose knob is not actuated and the two couplingstructures being decoupled when the dose knob is actuated. One or bothof the coupling structures can be present on a resilient member and thecoupling structures are shaped such that they provide either aunidirectional or a bidirectional ratchet coupling. During dose setting,the dose knob is rotated and the rotational forces of the dose knob aretransmitted to the scale drum via the ratchet coupling with the engagingteeth of the two coupling structures. The ratchet coupling is activated(e.g., the two coupling structures start to ratchet in thecircumferential direction) when the scale drum is in the maximum dose orminimum dose position and the user attempts to set a higher respectivelylower dose. For this purpose a bidirectional coupling is required. Whenthe user attempts to set a dose which exceeds the amount of medicationpresent in the cartridge (e.g., when the stop element is in the stopposition) the setting of that dose is prevented. A unidirectionalratchet coupling present between the dose knob and the scale drum canprevent damage to the drive and dosing mechanism. Thus a bidirectionalcoupling protects the stop zero dose, stop maximum (individual) dose andstop total dose mechanisms (preventing the setting of a dose exceedingthe amount present in the cartridge). A unidirectional coupling is usedfor the stop maximum (individual) dose and stop total dose mechanisms.

Preferably, a unidirectional coupling (preferably a ratchet) is locatedbetween the housing and the rotation member, which permits a rotation ofthe rotation member in a rotation direction (preferably in the secondrotation direction) and which does not permit a rotation in the oppositedirection (preferably the first rotation direction). For example, theunidirectional coupling may utilize a low torque, thus elasticallydeforming a resilient or elastic element (spring or retaining ratchet)of the unidirectional coupling resulting in a movement of the piston rodin the dispensing direction. Advantageously it can be achieved throughthis arrangement that upon trying to rotate the dose knob in the firstdirection, the rotation in the first direction is prevented when a catchabuts a stop limiter (e.g., when the stop element is in the stopposition). Preferably, the torque executed in the first rotationdirection on the dose knob is transmitted from the stop element to therotation member and from the rotation member via the unidirectionalcoupling to the housing whereby a rotation of the dose knob in the firstdirection is prevented when the stop element is in its stop position. Asan option, the overload protection described above can be added to thesystem thus protecting the components of the drive mechanism when thetorque is transmitted to the housing.

The unidirectional coupling between the housing and the rotation memberallows for a rotation of the rotation member in the second direction fordispensing a dose and is preferably designed as a ratchet system. Such aratchet system can, for example, be composed of meshing teeth present ontwo separate parts that are biased by an elastic member such as aspring. The meshing teeth have a steep and flat slope and allow for arotation in one direction only thereby generating clicks when the teethratchet versus each other. Thus on one hand the rotation of the rotationmember in the first rotation direction is prevented whereas the rotationin the second direction during dose dispensing is allowed and therebyproducing audible and/or tactile signals. The ratchet system absorbs apart of the energy provided by the drive mechanism and therefore affectsthe drive efficiency of the device. The latter is defined as the ratioof the out coming force acting on plug of the carpule by the piston rodand the incoming force from pushing the dose button or dose knob fordose delivery. The incoming axial forces are translated into rotationalmovements and the losses in the system define to what extend theincoming force will be transmitted to the plug of the carpule. Forexample the unidirectional ratchet system absorbs rotational moments forproducing the clicks and has frictional losses that can be reduced foroptimizing the device efficiency. Parameters for optimizing the efficacyare, for example the number of meshing teeth, slopes of the meshingteeth, radius of the ratchet system, height of the meshing teeth,materials used and, preferably, the biasing force for the ratchetsystem. The biasing force can be provided by flexible arms or a springmember and the biasing force can be optimized for the clickerfunctionality only. Frictional losses are proportional to the normalforce acting on the meshing teeth of the ratchet system and therefore ahigher force leads to higher frictional and/or moment losses. On theother hand a normal force which is too low prevents efficient clickingor adversely affects the unidirectional coupling features that theratchet system may have as well. Therefore there is an optimum regionfor the normal force that enables all functionalities of the ratchetsystem. The drive and dosing device of disclosed embodiments can haveimproved device efficiency and for that not only the unidirectionalratchet system for dose dispensing needs to be optimized. In theexemplary embodiments presented below the unidirectional ratchet systemfor dispensing and the ratchet system for dose setting can be powered bya single spring element or each system is powered by a separate spring,which is adjusted to its specific needs. Using one spring unit has theadvantage that only one part is needed but on the other hand needs tocompromise the spring forces for both ratchet systems. Using two or moresprings has the advantage that the spring forces are adjusted to thespecific needs and can optimize the device efficiency but this calls, onthe other hand, for two instead of one spring units.

A drive and dosing mechanism for an injection device is describedwhereby a cartridge containing a fluid product is attached or can beattached to the drive and dosing device comprising a tubular housing, apiston rod, a dose knob and a drive nut. The tubular housing having adistal end and a proximal end and the piston rod having an outer threadand being moveable in the distal direction with respect to the housingfor dispensing the product. The dose knob can be present at the proximalend of the housing and can be rotated during dose setting in a firstdirection or in a second direction which is opposite to the firstdirection. The drive nut has an inner thread that engages the outerthread of the piston rod and which is rotatable in a second directionfor dispensing the product. Whereby during dose setting the dose knob isrotated in the first direction out of the proximal end of the housingand a first ratchet system is coupled to the dose knob and ensures thatthe dose knob can be rotated over discrete angular steps therebyproducing dose setting clicks, the ratchet system being biased by afirst spring element. The dose knob can be moved back and forth from anon-actuated position to an actuated position over an actuation distanceagainst the resilient force of the first spring element. Whereby duringdose delivery the dose knob is actuated thereby decoupling the firstratchet system from the dose knob and coupling the drive nut to the doseknob and the dose knob is rotated in the second direction back into theproximal end of the housing whereby the rotation of the drive nut istranslated in a distal movement of the piston rod. Whereby a secondratchet system is coupled to the dose knob producing dose deliveryclicks, the second ratchet system being biased by a second springelement. For the two ratchet systems, the ratio of the spring forces ofthe first and second spring element is above unity.

Particularly in embodiments where a used (e.g., empty) cartridge can bereplaced by a new (e.g., filled) cartridge it is advantageous that theunidirectional coupling can be switched back and forth between anactivated state and a non-activated state. The unidirectional coupling,in its activated state, allows a rotation of the rotation member in thatrotation direction which enables the movement of the piston rod in thedispensing direction, particularly the second rotation direction, andprevents a rotation in the opposite direction, preferably the firstrotation direction. The unidirectional coupling, in its non-activatedstate allows a rotation of the rotation member in the oppositedirection, particularly the first rotation direction. The unidirectionalcoupling preferably takes its non-actuated position when the cartridgeholder is released from the housing or is attached to the housing butdoes not contain a cartridge. The unidirectional coupling can be in itsactuated state when the cartridge holder is attached to the housing withor without a cartridge. Two different embodiments arise here from,namely one embodiment where the cartridge holder activates a mechanismswitching the unidirectional coupling in its activated state or anotherembodiment where the cartridge activates this mechanism.

Notably, a switching element can be positioned between the cartridge orcartridge holder and the unidirectional coupling which, throughattachment of the cartridge holder, with or without a cartridge, ismoveable relative to the housing, particularly in the proximal directionand which switches the unidirectional coupling in its activated state.

The switching element can, by releasing the cartridge holder orcartridge, be moved or is moveable in the distal direction and switchthe unidirectional coupling in its non-activated state. Preferably, aspring is used which is tensioned by the movement of the switchingelement in the proximal direction and which moves the switching elementin the distal direction when the cartridge holder or cartridge isremoved.

The switching element can, for example, be arranged such that it isrotationally locked with respect to the housing but axially slidablealong its longitudinal axis. For example, the cartridge holder can beattached to the housing with a rotational movement. The cartridge holdercan have a drive surface, which functions as an activation element,which slides along the switching element upon rotation of the cartridgeholder relative to the housing or the switching element, and whichprovokes a movement of the switching element along the longitudinal axisof the housing. The cartridge holder can, for example, be attached tothe housing using a screw thread. Alternatively, the cartridge holdercan be attached to the housing using a bayonet lock. The advantage of abayonet lock is that it generally attaches the cartridge holder to thehousing with a rotation that is less than a full rotation relative tothe housing for example over an angle of 35°, 45° or 90°, preferablybelow or equal to 90°. The bayonet lock can be such that, relative tothe housing, initially a pure axial movement and subsequently a purerotational movement are needed for the attachment of the cartridgeholder to the housing. Alternatively, the bayonet lock can be shapedsuch that the cartridge holder executes a concurrent combined axial androtational movement relative to the housing for the attachment of thecartridge holder. More preferably, the bayonet lock is shaped such thatthe cartridge holder performs at the end of the connection a purerotational movement, this means without a movement of the cartridgeholder along the longitudinal axis of the housing.

For embodiments where the used cartridge can be exchanged by a new one,it is preferred that the piston rod can be reset (e.g., can be pushedback into the housing of the drive and dosing device, preferably intothe proximal direction). During reset, the piston rod is moved relativeto the housing in the proximal direction. This can be done by pushingagainst the distal end of the piston rod, for example with a finger of auser or a plug in a new cartridge, provided that the cartridge holder orcartridge is released, particularly when the unidirectional coupling isnot activated. For this purpose it is preferred that the pitch of themeshing threads of the rotation member and the piston rod is high enoughto prevent self-locking when the piston rod is reset against thedispensing direction when the unidirectional coupling is not activated.During the reset or movement of the piston rod in the proximaldirection, the rotation member rotates in that direction that isopposite to the rotation direction for dose dispensing. Particularly,during reset, the rotation member performs a rotation in the firstdirection with respect to the housing and/or piston rod. The piston rodis, preferably via the linear slide, rotationally locked relative to thehousing during reset of the piston rod.

The drive and dosing mechanism can be configured to automaticallyretract and/or advance the piston rod during reset of the device (e.g.,when an empty cartridge is replaced by a full cartridge). The automaticretraction of the piston rod into the housing facilitates the insertionof a full cartridge and the plug of the cartridge is not exposed toaxial forces because the proximal end of the plug will not touch thedistal end of the piston rod during insertion of the new cartridge. Sucha retraction mechanism can comprise a resilient member attached to andpresent around, on or inside the piston rod such as a spring (e.g.,compression or spiral) or a magnetic member or electromagnetic member.Such a resilient member is tensioned during advancement of the pistonrod and energy stored in the member is released during reset of thedevice to retract the piston rod. The automatic advancement of thepiston rod after reset (e.g., when a new cartridge has been inserted)prevents an air gap from being present between the distal end of thepiston rod and the proximal end of the plug of the cartridge. This willfacilitate the priming operation needed before setting and dispensing ofa dose since no air gap needs to be closed before dispensing the firstdose. The advancement of the piston rod can comprise a resilient membersuch as a compression or spiral spring, or a magnetic or electromagneticarrangement.

Notably during reset of the piston rod, the stop element is axially androtationally locked with respect to the piston rod such that the stopelement moves together with the piston rod relative to the housing inthe proximal direction.

The dose knob may be configured to not perform a rotational or axialmovement relative to the housing during reset of the piston rod.

In preferred embodiments, where the set dose may be easily readable, thedrive and dosing device has a scale drum that is directly or indirectlyat least rotationally locked, preferably also axially locked to the doseknob. In more preferred embodiments, the scale drum and the dose knobare connected as a single part or they are snapped, glued or weldedtogether. Particularly, the dose knob and the scale drum can behave as ajoint part. The scale drum can have a helical shaped dose scale arrangedpreferably at its outer surface. The dose scale encompasses preferably aplurality of individual dose values or at least symbols that represent aspecific dose whereby the values or symbols are arranged along a helicalcurve such that it results in a helical dose scale. The dose scale canhave values of, for example 0 IU to 60 IU or 80 IU or even more than 100IU, stepped in 1, 2, 5 or other units. As mentioned before, the housingcan have a region for viewing the set dose, preferably a viewing window,where the value or symbol of the dose scale can be read which representsthe current or actual set dose or the dose to be dispensed. The scaledrum performs, via a rotation of the dose knob, a screw type of motionrelative to the housing such that the value of the helical shaped scalemoves along or through the region for viewing the set dose.

In an example, the scale drum has a thread which preferably has the samepitch as the helical shaped dose scale, whereby the thread can be in athreaded engagement with the housing. The housing can, for example, havean inner thread and the scale drum an outer thread. Alternatively, thescale drum can have an inner thread and the housing can have an outerthread for the threaded engagement. The pitch of the thread or thethreaded engagement is preferably such that no self-locking occurs whenthe actuation member is actuated for the dispensing of a product,respectively is pushed in the distal direction along the propulsiondistance into the housing, such that the dose knob is screwed togetherwith the scale drum into the housing. Thus the scale drum performs viathe threaded engagement (e.g., with the housing) a translationalmovement with respect to the housing during dose setting and dosecorrection when the dose knob is rotated in the first or second rotationdirection. The distance travelled in the rearward direction depends onthe pitch of the thread between the scale drum and the housing, a highpitch implies a higher distance whereas a lower pitch results in a lowerdistance. Of course there are limits for the pitch, if the pitch is toohigh, then the user cannot push the dose button with the same hand thatholds the housing of the device since the dose knob/button is out ofreach. If the pitch is too low then the threading engagement runs intothe self-locking region which would prevent rotation of the dose knobback into the device during dose delivery. An additional aspect of thethread pitch of the dose scale is that it contributes to the gearingratio of the device. When the dose button is actuated and pushed backinto the proximal end of the housing, the dose knob is rotating and thisrotation is translated to a rotation of the rotation member and finallyinto a distal movement of the piston rod. The gearing ratio can bedefined by the ratio of the pitches of threads of the scale drum (and/ordose sleeve) and the piston rod (and/or rotation member), respectively.Thus, with a constant pitch of the thread of the piston rod, a highpitch of the scale drum results in a high gearing ratio therewithlowering the force for dispensing a product, but this at the cost of ahigher distance that needs to be travelled by the dose knob. On theother hand, a lower pitch of the thread of the scale drum lowers thedistance that the dose knob needs to travel for delivering a dose butthis at cost of a lower gearing ratio or higher forces need to beapplied by the user for dispensing a dose. In that context the deviceefficiency, or reduction of frictional/moment losses are important sincein the triangle of gearing ratio, travel distance and device efficiency,it may be advantageous for an embodiment to present a device having alow distance that the dose knob travels, with an low input force of theuser and a high output force on the plug of the cartridge.

In more preferred embodiments, the scale drum can be rotated back andforth between a zero dose position and a maximum dose position, wherebya stop zero dose prevents a rotation of the scale drum in the zero doseposition in the direction, preferably the second direction, whichreduces the dose and which allows for a rotation in the first direction,and whereby a stop maximum dose prevents a rotation of the scale drum inthe stop maximum dose position, preferably the first direction whichincreases the dose and which allows for a rotation in the seconddirection for reducing a dose. It is preferred that in the viewingwindow the maximum value of the dose scale can be read when the dosescale is in the maximum dose position and the dose zero can be read whenthe scale drum is in the zero dose position. The dose set in the maximumdose position is the dose that maximally can be dispensed with a singleinjection even when more product is available in the cartridge. The stopmaximum dose and/or the stop zero dose preferably act in thecircumferential direction and can be shaped as an anti-twist type ofarrester. Analogously, the same can apply for a maximum dosecounter-arrester and/or a zero dose counter-arrester.

In a first alternative, the stop maximum dose and/or the stop zero dosearresters can be established on the housing or an element fixed to thehousing which can be considered to be part of the housing like, forexample, an insert for the viewing window made from a transparent oropaque material, particularly a plastic material. Preferably the scaledrum can establish the maximum dose counter-arrester which in themaximum dose position abuts the stop maximum dose (arrester). The scaledrum or the dose knob can establish the zero dose counter-arrester whichabuts the stop zero dose (arrester) in the zero dose position.

In a second alternative, the stop maximum dose and/or the stop zero dose(arresters) can be located at, for example an intermediate sleeve,particularly the dose sleeve, which can be located between the dose knoband the stop element and which is rotationally secured with respect tothe dose knob. Preferably, the intermediate sleeve, particularly an endof a thread or of a thread element of the intermediate sleeve canestablish the stop maximum dose. Alternatively or additionally, theintermediate sleeve, particularly an end of the thread of theintermediate sleeve, particularly the end of the thread or threadelement which is opposite to the stop maximum dose, can establish thestop zero dose. Preferably, the stop maximum dose is located distallyversus the stop zero dose, or vice versa. The maximum dose counter-stopor counter arrester and/or the zero dose counter-stop or counterarrester can be established by, for example, a coupling member,particularly a coupling sleeve which is in a threaded engagement withthe intermediate sleeve, particularly the dose sleeve and which isrotationally secure and axially slidable connected with the scale drum.The coupling member can have an inner thread, particularly a threadsegment which engages an outer thread, particularly the thread of theintermediate sleeve which forms at least one out of stop maximum doseand stop zero dose, whereby it is preferred that one end of the threadsegment establishes the zero dose counter-stop (arrester) and the otherend of the same, or another thread segment, establishes the maximum dosecounter-stop (arrester).

The first and second alternatives can be combined. For example, the stopzero dose (arrester) and/or the zero dose counter-stop(counter-arrester) can be established according to the first alternativeand the stop maximum dose (arrester) and/or the maximum dosecounter-stop (counter-arrester) can be established according to thesecond alternative. Alternatively, the stop maximum dose (arrester)and/or the maximum dose counter-stop (counter-arrester) can beestablished according to the first alternative and the stop zero dose(arrester) and/or the zero dose counter-stop (counter-arrester) can beestablished according to the second alternative.

The catch of the stop element abuts the stop limiter and the stopelement prevents rotation of the scale drum in the rotation directionwhich results in a dose increase, when the scale drum is not in itsmaximum dose position and/or the amount of product present in thecartridge is below the dose of the maximum dose position of the scaledrum.

In other words, the maximum dose can be set and dispensed on the driveand dosing device as often as this maximum dose is actually present asproduct in the cartridge. If the amount of product present in thecartridge is below the maximum dose, then the stop limiter (arrester)and catch (counter-arrester) collide with each other and as such preventan increase of the dose setting.

The stop element is, in preferred embodiments, at least during the dosesetting and dispensing of the set dose torque-proof coupled to the scaledrum and/or dose knob. The coupling can be permanent, particularly inall operating conditions. For example, the stop element can beindirectly coupled to the scale drum and/or dose knob, for example viaan intermediate sleeve. As an alternative, the stop element can bedirectly coupled or engaged with the dose knob or scale drum.Preferably, the scale drum and/or the dose knob are moveable withrespect to the stop element along the longitudinal axis of the drive anddosing device.

In preferred embodiments at least one intermediate sleeve (e.g., thedrive sleeve and/or the dosing sleeve or a first and second couplingsleeve) can be kinematically located between the dose knob and the stopelement. The at least one intermediate sleeve can engage the stopelement such that it is axially slidable and rotationally secured. Theat least one intermediate sleeve is preferably rotationally secure andoptionally axially slidable coupled with the dose knob. This ensuresthat the rotation of the dose knob is transmitted to the stop element,which is rotated in the same rotation direction as the dose knob.

The stop element is coupled such with the dose knob such that the stopelement is screwed along the piston rod during dose setting (e.g.,during rotation in the first direction and/or rotation in the seconddirection and during dispensing of the set dose). Particularly, the stopelement is screwed towards the distal end of the piston rod when thedose is increased and it is screwed towards the proximal end of thepiston rod when the dose is decreased or dispensed. The mechanicalset-up according to disclosed embodiments ensures that in the zero doseposition immediately after dispensing of a set dose, the stop element isin the same position with respect to the piston rod as for the zero doseposition immediately before setting the dose to be dispensed. Forexample, the stop element in the zero dose position of the scale drumalways occupies the same position with respect to the piston rodindependently from the degree of filling of the cartridge or from thedispensing distance of the piston rod. Such a kinematic arrangementallows for a space-saving integration of the stop element in the driveand dosing device.

More preferably, the drive and dosing device has a dispense couplingwhich is closed upon actuation, preferably pushing, of the actuationmember by the user along the actuation distance and which is, or can be,opened by releasing the actuation member. Particularly the spring thatis stressed by the actuation of the actuation member and closure of thedispense coupling can open the dispense coupling and reset the actuationmember into its original position.

The rotation member is rotationally secured with the scale drum and/orthe dose knob when the dispense coupling is coupled and when theactuation member is actuated. The scale drum and/or the dose knob can berotated relative to the rotation member, when the dispense coupling isopen (e.g., when the actuation member is not actuated) or released(e.g., when the actuation member is in its non-actuated position).

The actuation member is not actuated for setting a dose whereby it isactuated for dispensing a dose. This implies that the dispense couplingis closed during the dose dispensing, whereby it is opened during thedose setting. The dispense coupling can, for example, have a firstcoupling structure and a second coupling structure that engage in a formfit engagement when the dispense coupling is closed and that disengagewhen the dispense coupling is open. Preferably, the coupling structurescan be brought in and out engagement with each other by movements alongthe longitudinal axis of the drive and dosing device. Provided that thedrive and dosing device has at least one intermediate sleeve, onecoupling structure can be permanently rotationally locked with theintermediate sleeve (e.g., with a drive sleeve) whereby the othercoupling structure can be, for example, located at the rotation member.The coupling structure that can be brought into engagement with therotation member is preferably permanently rotationally locked withrespect to the stop element. Thereby it is ensured that this couplingstructure follows the rotational movements of the stop element duringdial-up, dial down or dispensing of a dose.

A further aspect applies to the limitation of the dispensable amountfrom a cartridge. This aspect need not only be applied to the drive anddosing device described here, but also to, for example, mechanisms knownfrom the state of the art for restricting the dose setting as exemplarydescribed in the patent literature cited above. The applicant reservesthe option to claim this general aspect with a separate application orat least to pursue with claims directed hereupon.

The solution described in this context, particularly described in claims16 and 17 is based upon the problem to increase the therapeutic optionsfor injection devices that limit the dose setting in specific situationsand to provide for this purpose a simple and cost-efficient solution.

In the state of the art, preventing the setting of a dose which exceedsthe amount of product present in the cartridge is suggested. Disclosedembodiments may be used to prevent errors (e.g., inadequate dosing) fromoccurring when the user attempts to set a dose that cannot be dispensedwith the injection device because the amount of product present in thecartridge is not sufficient.

Usually, ampoules are used as cartridges often having a nominal volumeof 300 IU. It should be noted that the nominal volume is generally belowthe total volume of the cartridge. The nominal volume can be dispensedby moving the plug in the cartridge. The difference between the totalvolume and the nominal volume can be designated as the dead volumewhich, for example, due to the geometry of the plug and the cartridgehousing cannot be dispensed. The cartridges proposed in the state of theart refer, for the blockage of the last dose, to the nominal volume.

In an aspect of disclosed embodiments, it is supposed that from thecartridge of the injection device (e.g., preferably an ampoule) only afirst part (e.g., designated as dispensable volume of the nominalvolume) can be dispensed from the amount present in the cartridge (e.g.,as delivered). A second part, called the residual volume and which isabove 1 IU, remains in the cartridge. The residual volume could bedispensed by moving the piston rod, but such a movement is blocked bythe injection device. With the injection device, only the dispensablevolume of the nominal volume can be dispensed and the residual volume ofthe nominal volume cannot be dispensed. The total volume in thecartridge is composed of the dead volume and nominal volume. The nominalvolume is composed of the dispensable volume and the residual volume.

The injection device further has an elongated and preferablysleeve-shaped housing and a dose knob which can be rotated relative tothe housing in a first rotation direction for increasing a dose to bedispensed, and preferably can be rotated in second rotation directionopposite to the first rotation direction for decreasing a dose to bedispensed. For the design of the housing, the dose knob and the scaledrum it is referred to the embodiments described herein, independent ofthe design and integration of the stop element. The same applies to theactuation element.

A stop element, preferably rotationally coupled with the dose knob,performs during a rotation of the dose knob in the first direction(e.g., with an increase of the dose to be dispensed), a movement towardsa stop limiter. As a result, the distance, particularly measured along ahelix-shaped curve and which is particularly directly proportional tothe volume that can be dispensed, is reduced between the stop limiterand the stop element.

The stop element, coupled with the dose knob performs a movement awayfrom a stop limiter during a rotation of the dose knob in the seconddirection (e.g., with a decrease of the dose to be dispensed). As aresult, the distance, particularly measured along a helix-shaped curveand which is particularly directly proportional to the volume that canbe dispensed, is increased between the stop limiter and the stopelement.

Preferably, the stop element engages a thread, along which it can bescrewed during a rotation of the dose knob. The thread preferablyprovides the helix-shaped curve.

The stop element does not move with respect to the stop limiter duringthe dispensing of a set dose (e.g., the stop element stands still withrespect to the stop limiter), but it can, for example, move with respectto the housing.

The injection device preferably has a dispensing coupling which can becoupled through actuation, preferentially pushing of an actuationelement, particularly a dose button (or a combined dose-knob-dose-buttonas described previously) at the proximal end of the injection device.The dispensing coupling couples the stop limiter and the stop elementsuch that the stop element and the stop limiter are moveable relative toeach other when the actuation element is not actuated (e.g., is in itsnon-actuated position), and the stop element and the stop limiter arenon-moveable with respect to each other (particularly rotationallysecured) when the actuation element is actuated (e.g., is in itsactuated position).

If the stop element abuts the stop limiter, then the setting of a dosethat would result in dispensing part of the residual volume isprevented. In other words, the setting of a dose can be prevented whichwould result in less than the residual volume of the nominal volumeremaining in the cartridge. With the device only the dispensable volumeand not the residual volume or a part of the residual volume can bedispensed.

Injection devices can be produced cost effectively by changes in theassembly of injection devices described herein and devices known fromthe state of the art. First, the nominal volume of the cartridge for theinjection device is defined. Then the dispensable volume is defined. Theinjection device is assembled such that only the dispensable volumewhich is below the nominal volume can be dispensed, and the residualvolume of the nominal volume cannot be dispensed. This is done bypositioning the stop element at a distance with respect to the stoplimiter, the distance being measured along a helical curve whereby thedistance is directly proportional to the dispensable volume. For thedevices known from the state of the art, this distance is directlyproportional to the nominal volume.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the individual parts of a drive and dosingdevice according to a first embodiment.

FIG. 2a shows a drive and dosing device of the first embodiment in aninitial state with a filled cartridge.

FIG. 2b shows a sectional view of the device of FIG. 2a rotated alongthe longitudinal axis by 90°.

FIG. 3 shows the device of FIGS. 2a and 2b in a maximum dose positionand with the dose button in a non-actuated position.

FIG. 4 shows the device of FIG. 3 with an actuated dose button.

FIG. 5 shows the device according to the first embodiment in a zero doseposition after the dose set in FIGS. 3 and 4 has been dispensed.

FIG. 6 shows the device according to the first embodiment whereby a doseincrease is blocked by the stop element.

FIG. 7 shows the device according to the first embodiment in a zero doseposition after dispensing of the dose set in FIG. 6.

FIG. 8 shows the device according to the first embodiment with thecartridge and the cartridge holder removed from the drive and dosingdevice.

FIG. 9 shows the drive and dosing device according to the firstembodiment after a piston rod has been reset and a new cartridge and acartridge holder can be connected.

FIG. 10a shows the device according to the first embodiment after a newcartridge is inserted and the dose button is actuated in the zero doseposition.

FIG. 10b shows a sectional view of the device of FIG. 10a rotated alongthe longitudinal axis by 90°.

FIG. 11 is an exploded view of the individual parts of a drive anddosing device according to a second embodiment.

FIG. 12a shows a drive and dosing device according to the secondembodiment in the zero dose position.

FIG. 12b shows a cross sectional view of the drive and dosing deviceshown in FIG. 12a taken along the line A-A in FIG. 12 a.

FIG. 12c shows a cross sectional view of the drive and dosing deviceshown in FIG. 12a taken along the line B-B in FIG. 12 b.

FIG. 13a shows the drive and dosing device of FIG. 12a in a maximum doseposition.

FIG. 13b shows a cross sectional view of the drive and dosing deviceshown in FIG. 13a taken along the line C-C in FIG. 13 a.

FIG. 13c shows a cross sectional view of the drive and dosing deviceshown in FIG. 13a taken along the line D-D in FIG. 13 b.

FIG. 14a shows the drive and dosing device of FIG. 13a after the doseset in FIG. 13a has been completely dispensed.

FIG. 14b shows a cross sectional view of the drive and dosing deviceshown in FIG. 14a taken along the line E-E in FIG. 14 a.

FIG. 14c shows a cross sectional view of the drive and dosing deviceshown in FIG. 14a taken along the line F-F in FIG. 14 b.

FIG. 15a shows the drive and dosing device of FIG. 12a with the stopelement in the stop position.

FIG. 15b shows a cross sectional view of the drive and dosing deviceshown in FIG. 15a taken along the line G-G in FIG. 15 a.

FIG. 15c shows a cross sectional view of the drive and dosing deviceshown in FIG. 15a taken along the line H-H in FIG. 15 b.

FIG. 16a shows the drive and dosing device of FIG. 15a after the doseset in FIGS. 15a-15c has been dispensed.

FIG. 16b shows a cross sectional view of the drive and dosing deviceshown in FIG. 16a taken along the line R-R in FIG. 16 a.

FIG. 16c shows a cross sectional view of the drive and dosing deviceshown in FIG. 16a taken along the line S-S in FIG. 16 b.

FIG. 17a shows the drive and dosing device of the second embodimentafter unidirectional coupling has been de-activated.

FIG. 17b shows a cross sectional view of the drive and dosing deviceshown in FIG. 17a taken along the line K-K in FIG. 17 a.

FIG. 17c shows a cross sectional view of the drive and dosing deviceshown in FIG. 17a taken along the line M-M in FIG. 17 b.

FIG. 18a shows the drive and dosing device of FIG. 17a after the pistonrod has been reset.

FIG. 18b shows a cross sectional view of the drive and dosing deviceshown in FIG. 18a taken along the line J-J in FIG. 18 a.

FIG. 18c shows a cross sectional view of the drive and dosing deviceshown in FIG. 18a taken along the line L-L in FIG. 18 b.

FIG. 19 is an exploded view of the individual parts of a drive anddosing device according to a third embodiment.

FIG. 20 is a cross sectional view of a drive and dosing device accordingto the third embodiment in an initial state before setting of a dose.

FIG. 21 shows detail of cross sectional view of a drive and dosingdevice according to the third embodiment in an initial state beforesetting of a dose.

FIG. 22 is a cross sectional view of a drive and dosing device accordingto the third embodiment, after setting of a dose.

FIG. 23 is a cross sectional view of a drive and dosing device accordingto the third embodiment, after setting of a dose and actuation of thedose knob.

FIG. 24 is a cross sectional view of a drive and dosing device accordingto the third embodiment after dispensing of the set dose and having anactuated dose knob.

FIG. 25a is a detail cross sectional view of a drive and dosing deviceaccording to the third embodiment after setting of a dose and having anon-actuated dose knob.

FIG. 25b is a detail cross sectional view of a drive and dosing deviceaccording to the third embodiment, after setting of a dose and having anactuated dose knob.

FIG. 26 is a cross sectional view of a drive and dosing device accordingto the third embodiment in which the setting of a higher dose isprevented by the stop element being in the stopping position.

FIG. 27 is a cross sectional view of a drive and dosing device accordingto the third embodiment after the dose set in FIG. 26 has beendispensed.

FIG. 28 is a cross sectional view of a drive and dosing device accordingto the third embodiment after the cartridge holder has been removed.

FIG. 29a is a detail cross sectional view of a drive and dosing deviceaccording to the third embodiment with the device in an initial statewith cartridge holder attached to the drive and dosing mechanism.

FIG. 29b is a detail cross sectional view of a drive and dosing deviceaccording to the third embodiment with the device in an initial statewith cartridge holder removed from the drive and dosing mechanism.

FIG. 30a shows device efficiency (F_(out)/F_(in)) versus the user inputforce (F_(in)) for the device according to the first embodiment havingone dose spring. Data are shown for 3 different stroke lengths: 25 mm,30 mm and 33 mm.

FIG. 30b shows device efficiency (F_(out)/F_(in)) versus the user inputforce (F_(in)) for the device according to the third embodiment having aseparate dose spring and a reset spring. Data are shown for 3 differentstroke lengths: 25 mm, 30 mm and 33 mm.

DETAILED DESCRIPTION

In FIGS. 1-10, the first embodiment of a drive and dose settingmechanism is presented with a housing 4, 18 having an external housing18 and a housing insert or mechanic holder 4 that is concentricallyarranged within the external housing. The mechanic holder 4 isrotationally and axially fixed to the external housing 18. The housing4, 18, more specifically the mechanic holder 4 has a threading 4 aengaging with an internal thread of the scale drum 9 such that the scaledrum can be screwed along the longitudinal axis L of the housing 4, 18.The scale drum 9 is axially and rotationally fixed to the dose knob 10.In an example, they are snapped together. The user of the drive and dosesetting mechanism can hold the dose knob 10 which is rotatable versusthe housing 4, 18. The set dose will be increased upon rotation of thedose knob 10 in a first direction whereas the dose will be decreasedupon rotation into a second direction which is opposite to the firstdirection. Rotation of the dose knob 10 in the first direction ensuresthat the scale drum 9 will be screwed away from the proximal end of thehousing 4, 18 and the scale drum 9 will be screwed into the housing 4,18 upon rotation in the second direction.

The housing 4, 18 (e.g., the external housing 18) has an area forviewing the set dose 18 a, such as a viewing window in the externalhousing 18. The area for viewing the set dose 18 a enables the user toread the set dose from the scale drum 9. The scale drum 9 shows on itsouter surface a helical shaped scale with a plurality of consecutivenumbers. In the shown example the scale runs from 0 to 60 in steps of 2.The numbers represent a dose in International Units (IU). For thesetting of a dose of 30 IU, the dose knob 10 is rotated versus thehousing 4, 18 until the value of 30 can be read through the viewingwindow 18 a. At the proximal end of the drive and dosing mechanism,there is an actuation element 21 in the form of a dose button and thisis the proximal end of the drive and dose setting mechanism. The dosebutton 21 is arranged in the dose knob 10 such that is can be displacedalong an actuation distance relative to the dose knob 10.

The dose button 21 possesses for example a circumferential protrusion 21a on its outer surface that engages with an internal rim 10 b of thedose knob 10. In FIGS. 2a, 2b and 3, the dose button 21 is, for example,shown in its non-actuated state. FIGS. 4 and 10 a, 10 b show the dosebutton 21 in its actuated state and the dose button is displaced overthe actuation distance compared to FIG. 3. The dose button 21 is locatedat the proximal end of the mechanism and can be easily depressed. Forexample, the dose button 21 may be actuated by the thumb of a usergrabbing the housing 4, 18 with his hand.

For dispensing the set dose, the dose button 21 is depressed further inthe distal direction such that the dose knob 10 together with the scaledrum 9 can be screwed into the housing 4, 18 (compare FIGS. 4 and 5).The dose button 21 and the dose knob 10 are axially displaced versus thehousing 4, 18.

At the distal end of the housing insert 4, respectively the housing 4,18 is a cartridge holder 11 containing a cartridge or ampoule 11 a. Theampoule 11 a has at its distal end a septum which can be pierced by aneedle. The ampoule also has a plug which can be moved in a dispensingdirection (e.g., towards the septum) whereby the liquid product locatedbetween the septum and the plug (for example insulin) can be dispensed.The plug is operatively connected to a piston rod 19 having a multiplethreading 19 a on the outside engaging an internal threading 13 a of arotating member 13, 15. The rotating member 13, 15 includes, in theshown example, of two parts with a threaded nut 13 and a drive nutsocket 15 which are axially and rotationally locked to each other.Between the threaded nut 13 and the drive nut socket 15 exists acircumferential notch which is engaged with a part of the housing 4, 18,namely the housing insert 4 such that the rotating member 13, 15 isrotatable versus the housing insert 4 but is not axially displaceable.

A linear slide 2, which is rotationally locked with respect to thehousing 4, 18 and which is axially not displaceable or at least limiteddisplaceable (for example in the range of a few millimeters, e.g., lessthan 5 mm) along the longitudinal axis L, guides the piston rod 19 suchthat the piston rod cannot rotate versus the housing 4, 18. However, thepiston rod 19 is axially displaceable along the longitudinal axis Lrelative to the linear slide 2. The piston rod 19 has a guiding notchand/or longitudinal notch 19 d that is superimposed on the externalthread 19 a and which is oriented parallel to the longitudinal axis L.The linear slide 2 engages with the guiding notch 19 d such that thepiston rod 19 is rotationally secured but can be axially displaced alongthe longitudinal axis L relative to the linear slide 2.

The drive and dosing mechanism has a rotating member 13, 15 which duringdose setting (e.g., increasing or decreasing a dose) is rotationallysecured with respect to the piston rod 19 and/or the housing 4, 18 andwhich during dose delivery is rotated relative to the piston rod 19and/or the housing 4, 18, more particular in the second rotationdirection of the dose knob 10. The rotating member 13, 15 follows therotation of the dose knob 10 during dose delivery. The rotating member13, 15 engages the external thread 19 a of the piston rod by an internalthread 13 a of the threaded nut 13. The rotating member is connected tothe housing 4, 18, more specifically to the housing insert 4, such thatit is axially not displaceable but rotatable versus the housing. Therotating member 13, 15 may have two parts, namely a threaded nut 13 anda drive nut socket 15, which are rotationally and axially locked to eachother and behave like a single part. The threaded nut 13 (e.g., drivenut) is made from a polymeric material, for example Teflon, which formsa low friction bearing couple with the piston rod 19. The drive nutsocket 15 is made from a polymeric material having strength higher thanthe strength of the threaded nut 13 (e.g., a fiber reinforced polymer).Between the threaded nut 13 and the drive nut socket 15 exists acircumferential groove that engages a part of the housing 4, 18 or apart that is fixed to the housing, in this example housing insert 4. Forinstance the threaded nut 13 and the drive nut socket 15 establish theborders of the circumferential groove. This simplifies the mounting ofthe rotating member 13, 15. Preferentially, the rotation member 13, 15is axially non-displaceable with respect to the housing 4, 18 during alloperation conditions.

A dispense coupling 81, 82 is closed if a user depresses the dose button21 in the distal direction and is opened upon release of the dose button21. The dispense coupling 81, 82 couples the rotating member 13, 15torque-proof with the dose knob 10 when the dispense coupling 81, 82 isclosed. The dose knob 10 is rotationally decoupled from the rotationmember 13, 15 if the dispense coupling 81, 82 is decoupled (e.g., thedose knob can be rotated versus the rotating member 13, 15).

The dispense coupling 81, 82 may have a first coupling structure 81(also called a first dispensing coupling structure) and a secondcoupling structure 82 (also called a second dispensing couplingstructure), which are brought into a torque-proof engagement when thecoupling 81, 82 is closed. The coupling 81, 82 furthermore comprises adose spring 5, which spring force tends to disengage the first couplingstructure 81 and the second coupling structure 82. The dispense coupling81, 82 is closed upon actuation of the dose button 21 and the first andsecond coupling structures are brought into a rotationally secureengagement, thereby compressing the dose spring 5. The dose spring 5also serves the purpose of resetting the dose button 21 into thenon-actuated position.

In the shown example, the first coupling structure 81 iscircumferentially arranged internal teeth (e.g., toothing) whereas thesecond coupling structure 82 is circumferential arranged external teeth,whereby the first and second coupling structures 81, 82 can be broughtinto engagement by an axial displacement along the longitudinal axis L.In particular, the second coupling structure 82 is rotationally lockedwith respect to the rotating member 13, 15. Preferably, the secondcoupling structure 82 is part of the rotating member 13, 15, morepreferably part of the drive nut socket 15.

The first coupling structure 81 can be, for example, a drive sleeve 8which can be geometrically and/or kinematically arranged between therotating member 13, 15 and the dose button 21. The drive sleeve 8 isdisplaced relative to the housing 4, 18 and/or piston rod 19 in thedistal direction along the longitudinal axis L upon depressing the dosebutton 21. Upon release of the dose button 21, the drive sleeve will bedisplaced in the proximal direction due to the energy stored within thedose spring 5.

The drive sleeve 8 is preferably permanently (more preferably duringdose setting and dose dispensing) torque-proof engaged with the doseknob 10. Preferably, the first coupling structure 81 is permanentrotationally locked with the dose knob 10.

Located between the drive sleeve 8 and the dose button 21 is a dosesleeve 7, which is rotationally locked and axially displaceable withrespect to the drive sleeve 8. The dose sleeve 7 possesses on its innersurface one or more guiding keys 7 c which are arranged along thelongitudinal axis L and which engage one or more guiding grooves, whichare arranged on the outside surface of the drive sleeve 8 such that anaxially displaceable but rotationally locked connection exists betweenthe dose sleeve 7 and the drive sleeve 8.

The dose sleeve 7 has a thread 7 b on the outside surface, which islimited on its distal end by a stop maximum dose 7 e, and by a stop zerodose 7 d on its proximal end. A coupling sleeve 6 has an internal thread6 b engaging with the thread 7 b. In FIG. 1, the internal thread segment6 b is visible on the outside as a depression although it is an internalthread segment. This is done for manufacturing purposes, the depressionson the outside prevent material accumulation during the injectionmolding process. The at least one internal thread segment 6 b has an endalong the circumferential direction that forms a maximum dose limiter,and it touches the stop maximum dose 7 e when the dose knob 10 is in themaximum dose position and is rotated in the first direction. The atleast one internal thread segment 6 b has an end along the oppositecircumferential direction which forms a zero dose limiter, and ittouches the stop zero dose 7 d when the dose knob is in the zero doseposition and is rotated in the second direction. The thread 7 b is amultiple thread, in the shown example a quadruple thread. In particular,the thread 7 b can have the same pitch as the thread 4 a.

As an alternative, the housing insert 4, respectively the housing 4, 18can have the stop zero dose 4 c, for example at the distal end of thread4 a. The counter member for the stop zero dose can be formed, forexample at the inner surface of the scale drum 9. For example, thecounter member for the stop zero dose can be an end of the internalthread or internal thread segment of the scale drum 9 that engages thethread 4 a.

The dose sleeve 7 is preferably permanently rotationally fixed butaxially slidably connected to the dose knob 10. Therefore, the dosesleeve 7 has keys 7 a, which extend along the longitudinal axis L andengage with one or more recesses 10 a of the dose knob 10.

Positioned between the housing insert 4 and the dose sleeve 7 is theclutch 6, which is shaped as a coupling sleeve and also called couplingsleeve 6. The coupling sleeve 6 is engaged with the internal housing 4such that it is rotationally secured but axially slidable. The couplingsleeve 6 has on its outer surface one or more splines 6 a which engagewith a notch of the housing insert 4 that is arranged parallel to thelongitudinal axis L. The coupling sleeve 6 has an internal thread whichengages the thread 7 b of the dose sleeve 7.

The dose button 21 is connected to the proximal end of the dose sleeve 7such that it can rotate freely.

A unidirectional coupling 71, 72, 73, 74 (which is generally referencedbelow as 70) is located in the housing 4, 18. During the dose settingand/or delivery the unidirectional coupling 70 does not permit arotation in the first direction of the rotation member 13, 15 relativeto the housing 13, 15 and/or piston rod 19 whereas it permits a rotationin the second direction. The unidirectional coupling 70 can be shaped asa ratchet. The unidirectional coupling 70 prevents rotation of therotation member 13, 15 in the first direction during increasing a dosesetting due to frictional forces potentially occurring between the doseknob 10 and the rotation member 13, 15 or due to elastic forcesoriginating from the plug in cartridge 11 a which tend to push thepiston rod 19 into the proximal direction.

The unidirectional coupling 70 can act as a permanent, non-releasablecoupling as far as the drive and dose setting mechanism is used as adisposable component (e.g., a component which will be disposed aftercompletely emptying the cartridge 11 a). If the drive and dose settingmechanism is intended for repeated use (e.g., the cartridge 11 a can bereplaced by another cartridge 11 a) it is preferred that theunidirectional coupling 70 can be released during exchange of acartridge whereby the rotation member 13, 15 can be rotated in the firstdirection relative to the housing 4, 18 such that the piston rod 19 canbe reset in its original position.

The unidirectional coupling 70 has a first coupling structure 71 and asecond coupling structure 72, whereby the first and second couplingstructures 71, 72 engage such that they are only rotatable in onedirection versus each other. The first coupling structure 71 can be, forexample, locked to the housing 4, 18 or at least rotationally locked tothe housing 4, 18, for example to a switching element 12. The secondcoupling structure 72 can, for example, be formed by the rotation member13, 15, more preferably the drive nut socket 15 or at least from a partthat is at least temporarily rotationally connected to the rotationmember 13, 15, such as coupling ring 14 or shaped onto coupling ring 14.The coupling ring 14 is preferably rotationally locked and axiallymoveable with respect to the rotation member, at least during dosesetting and dose dispensing. Particularly, the first and second couplingstructures 71, 72 are engaged by a spring, preferably dose spring 5.Preferably, the first coupling structure 71 and the second couplingstructure 72 encompass circumferentially arranged saw tooth structures.The first coupling structure 71 preferably points into the proximaldirection and the second coupling structure 72 points in the distaldirection. The teeth of the first coupling structure 71 and the secondcoupling structure 72 preferably point to each other. The saw teeth ofthe coupling structures 71, 72 have a steep and a flat face, whereby theflat face of one coupling structure can slip over the flat face of theother coupling structure, whereby the second coupling structure 72 canrotate relative to the first coupling structure 71 in the seconddirection. The steep faces of the coupling structures 71, 72 are pressedtogether at the attempt of rotating the second coupling structure 72 inthe first direction relative to the first coupling structure 71, therebypreventing rotation of the second coupling structure in the firstdirection.

For setting a dose, the dose knob 10 is rotated in the first directionrelative to the housing 4, 18 and the dose knob 10 is rotated out of theproximal end of the housing 4, 18 together with the scale drum 9 (see,e.g., FIG. 3). The set dose can be read from the dose scale 9 b in theviewing window 18 a. The dispense coupling 81, 82 is decoupled duringthe dose setting. In FIG. 3, the device is presented after a dose hasbeen set and that can be dispensed.

For dispensing a set dose as shown in FIG. 3, the dose button 21 ispressed in the distal direction versus the dose knob 10 along anactuation distance (compare FIGS. 3 and 4) whereby the dose sleeve 7 isalso displaced versus the housing 4, 18 along the actuation distance ofthe dose button 21. The coupling sleeve 6 is displaced in the distaldirection over the actuation distance of the dose button 21 due to thethread engagement that exists between the dose sleeve 7 and the couplingsleeve 6. The coupling sleeve 6 pushes the drive sleeve 8 also in thedistal direction, particularly over the actuation distance of the dosebutton 21. As a result, the first coupling structure 81 present at thedrive sleeve 8 is brought into a rotationally stable engagement with thesecond coupling structure 82 present at the rotation member 13, 15thereby closing the coupling structure 81, 82. The device is shown inFIG. 4 with an actuated dose button 21.

Upon pressing the dose button 21 in the distal direction, the dose knob10 is screwed back into the housing 4, 8 along a distance correspondingto the set dose (compare FIGS. 4 and 5). Hereby the dose knob rotatesand the set dose value counts back as can be seen through the viewingwindow 18 a. The rotational movement of the dose knob 10 is transferredto the dose sleeve 7 and the drive sleeve 8 and from the drive sleeve 8to the rotation element 13, 15 via the coupled dispense coupling 81, 82.As a result, the rotation element 13, 15 rotates relative to the housing4, 18 and/or piston rod 19 in the second direction, identical to therotation direction of the dose knob 10. Due to this rotational movement,the piston rod moves in the distal direction, whereby the piston rod 19is rotationally locked with respect to the housing 4, 18 by the linearslide 2. The flange at the distal end of the piston rod 19 pushesagainst the plug of the cartridge 11 a and moves the plug in thedispensing direction for dispensing the set dose. The piston rod 19moves along a dispensing distance whereas the dose knob moves along adose setting distance whereby the dose setting distance is proportionalto and above the dispensing distance resulting in a gearing from theforce applied to the dose button 21 to the plug of the cartridge.

This procedure can be repeated several times whereby each time anindividual dose can be set.

The device is shown in FIG. 6 with a volume present in the cartridge 11a which is below the maximum dose that can be set on the device. Thedevice has a stop element 20 in order to prevent setting a doseexceeding the dispensable volume present in the cartridge 11 a. The stopelement 20 is a sleeve shaped nut having an internal thread 20 bengaging with the thread 19 a of the piston rod 19. Furthermore, thestop element 20 is rotationally secured and axially slidably engagedwith the drive sleeve 8. The drive sleeve 8 has, for example, at leastone circumferentially arranged longitudinal notch engaging at least onerim 20 c arranged on the outer surface of the stop element 20.

Additionally, the stop element 20 has, particularly at its distal end, acatch 20 a shaped as a surface with a normal oriented towards thecircumferential direction. The rotation member 13, 15, particularly thedrive nut socket 15 has a stop limiter 15 a shaped as a surface with anormal pointing in the circumferential direction. The distance along thehelical shaped curve, notably along the thread 19 a between the stoplimiter 15 a and the catch 20 a, corresponds to the dose which can beset and/or the dose or volume which still can be dispensed from thecartridge.

The stop element 20 is preferably permanently torque-proof connected tothe dose knob 10 so that rotations of the dose knob 10 during the dosesetting and dispensing are transferred to the stop element. The stopelement 20 and the piston rod 19 are shown in FIGS. 2a and 2b in aninitial position or zero dose position when a dose of zero has been set.If the dose knob 10 is rotated in a first direction with respect to thepiston rod 19 for increasing a dose, then the stop element 20, which isrotationally secured with the dose knob 10, also rotates with respect tothe piston rod 19 whereby the stop element 20 is screwed in the distaldirection with respect to the piston rod 19 and the housing 4, 18 (see,e.g., FIG. 3). If the dose knob 10 is rotated in the second directionwith respect to the housing 4, 18 for correcting a dose, then the stopelement 20 is screwed relative to the piston rod 19 and the housing 4,18 in a proximal direction.

If the dose knob 10 is rotated in the second direction for delivering adose (e.g., when the dose button pressed) then the stop element 20 isscrewed relative to the piston rod to its proximal end whereby the stopelement maintains its position with respect to the housing 4, 18 and/orrotation member 13, 15 along the longitudinal axis L. During dosedelivery, the stop element is only subjected to a rotational movementwithout an axial movement relative to the housing 4, 18. Preferably, thestop element is rotationally locked with respect to the rotation member13, 15. This implies that the distance between the stop limiter 15 a andthe catch 20 a does not change during dose delivery. At the end of thedose delivery (e.g., when the zero value can be read from the viewingwindow) the stop element will be at substantially the same location asbefore the setting of the dose which was delivered (compare FIGS. 2a, 2bwith FIG. 5).

If the volume present in the cartridge 11 a is below the maximum dosewhich can be set, then the catch 20 a of the stop element 20 abuts thestop limiter 15 a when the dose knob 10 is rotated in a first directionfor increasing a dose. At the attempt of rotating the dose knob 10 inthe first direction, the dose knob 10 will be blocked from furtherrotating due to abutting of the stop element 20 with the rotation member13, 15. Setting a dose which exceeds the dispensable amount of productpresent in the cartridge 11 a will be prevented.

In an alternative which is not shown here, the distance between thecatch 20 a and the stop limiter 15 a is less compared to the shownembodiment (e.g., the stop element is more to the left in the drawings),which results in an earlier blocking of the rotation of the dose knob 10in the first direction. A residual volume will remain in the cartridge11 a which is the difference between the nominal volume in the cartridge11 a and the dispensable volume. In the alternative, setting a dose isprevented that would result in that in the cartridge 11 a less than theresidual volume of the nominal volume would remain.

The dose button 21 is actuated for dispensing the dose as set in FIG. 6and the dose knob 10 is rotated back into the housing over thedispensing distance. After dispensing (see, e.g., FIG. 7), the stopelement 20 is located at the same location with respect to the pistonrod 19 as the zero dose position of the previous dispensings (see, e.g.,FIGS. 2a, 2b , 5).

The cartridge holder 11, which can hold the cartridge 11 a, can bereleased and removed from the drive and dosing device for embodimentswhere an empty cartridge holder 11 a (see, e.g., FIG. 8) can be replacedby a new cartridge holder 11 a (see, e.g., FIG. 9). The empty cartridge11 a is removed from the cartridge holder 11 and a new cartridge 11 a isinserted in the proximal end of the cartridge holder 11. The cartridgeholder 11 is connected to the drive and dosing device using a bayonetconnector or a plug-and-rotate connector.

The cartridge holder 11 has at its outer surface a protrusion 11 b and acircumferential collar 11 d extending along the outer surface. Thehousing 4, 18, particularly the housing insert 4 has a bayonet slot 4 bwith an axial section parallel to the longitudinal axis L and acircumferential section which is connected to the axial section. Whenthe cartridge holder 11 is connected, the protrusion is located in thecircumferential section of the bayonet slot 4 b (see, e.g., FIG. 7). Thecollar 11 d abuts the distal end of the housing 4, 18, more particularlythe housing insert 4. For removing the cartridge holder 11, thecartridge holder 11 is rotated with respect to the housing 4, 18 suchthat the protrusion 11 b moves into the direction of the axial sectionof the bayonet slot 4 b. Once arrived, the cartridge holder 11 can bepulled along the longitudinal axis L and can be removed from the driveand dosing device. This procedure is reversed for attaching thecartridge holder 11 to the drive and dosing device. The cartridge holder11 is moved towards the distal end of the drive and dosing device,whereby the protrusion 11 b is pushed in the axial section of thebayonet slot 4 b. Rotation of the cartridge holder 11 relative to thehousing 4, 18 moves the protrusion 11 b in the circumferential sectionof the bayonet slot 4 b, fixating the cartridge holder 11 to thehousing. In particular, the collar lid is pushed against the distal endof the housing insert 4.

The cartridge 11 a, which can be held by the cartridge holder 11, isgenerally made from plastic or glass. The length of the cartridge 11 issubjected to relatively high dimensional tolerances, for example in therange of a couple of tenths of millimeters. The device shown in FIGS.1-10 b has a mechanism that ensures that the cartridge 11 a, despite thehigh manufacturing tolerances, is tightly locked by the cartridge holder11. Part of this mechanism is the linear slide 2 which, via the proximalend of the cartridge 11 a, can be moved along the longitudinal axis Lrelative to the housing. A cartridge spring 3, which can also be calleda tolerance compensation spring, acts upon the linear slide 2. Thecartridge spring is retained at its distal end by the linear slide 2 andat its proximal end by the housing 4, 18, more particularly the housinginsert 4. The proximal end of the cartridge 11 a touches the linearslide 2 upon attaching the cartridge holder 11 to the drive and dosingdevice whereby the linear slide 2 is moved into the proximal directionthereby tensioning the cartridge spring 3. The cartridge spring 3ensures that the cartridge is axially secured in the cartridge holder11. Dimensional tolerances for the length of the cartridge 11 a can becompensated for by the resilient nature of the linear slide 2. Thelinear slide 2 is located between the proximal end of the cartridge 11 aand the cartridge spring 3.

Upon releasing the cartridge holder 11 from the drive and dosing device,the linear slide 2 is moved in the distal direction along thelongitudinal axis L and relative to the housing 4, 18 due to thepreloaded cartridge spring 3.

As can be observed in FIGS. 8 and 9, the piston rod 19 may be reset toits original position for insertion of a new cartridge 11 a.

The unidirectional coupling 70 can be switched from its active state,blocking the rotation in the first direction of the rotation member 13,15, into an inactive state thereby allowing rotation of the rotationmember 13, 15 in the first direction.

The coupling 70 has a third coupling structure 73 at the coupling ring14 and a fourth coupling structure 74 present at the rotation member 13,15, preferably at drive nut socket 15. If the cartridge holder 11 isattached to the drive and dosing device, then the third couplingstructure 73 and the fourth coupling structure 74 are in a rotationallysecured engagement such that the rotation member 13, 15 is rotationallylocked with the coupling ring 14 (e.g., in both rotation directionstorque-proof engaged). The cartridge holder 11 is coupled to the thirdcoupling structure 73 such that the third coupling structure 73disengages from the fourth coupling structure 74 when the cartridgeholder 11 is released from the drive and dosing device, particularlywhen the cartridge holder 11 is moved in the distal direction relativeto the housing 4, 18. The coupling 70 is then in its inactive state. Thecartridge holder 11 is coupled with the third coupling structure 73 suchthat upon attachment of the cartridge holder 11 to the drive and dosingdevice the third coupling structure 73 is moved into the coupled statewith the fourth coupling structure 74. The third coupling structure 73is thereby moved in the proximal direction along the longitudinal axis Lwith respect to the housing 4, 18. Notably, the third coupling structure73, more specifically the coupling ring 14 having the third couplingstructure, can be moved against the force of dose spring 5 in theproximal direction, thereby straining the dose spring 5. Particularly,the dose spring 5 can move the third coupling structure 73, moreparticularly the coupling ring 14, in the distal direction when thecartridge holder 11 is released from the housing 4, 18. Hereto, the dosespring 5 supports the coupling ring 14, more particularly with itsdistal end.

The third coupling structure 73 preferably has internal teeth, wherebythe fourth coupling structure 74 has external teeth.

The third coupling structure 73, particularly the coupling ring 14 iscoupled with the cartridge holder 11 via the switching element 12 whichitself is rotationally secured and axially slidable along thelongitudinal axis L with respect to the housing 4, 18. In the exampleshown, the switching element 12 is coupled to the cartridge holder 11such that a rotation of the cartridge holder 11 relative to the housing4, 18 results in an axial movement of the switching element 12 along thelongitudinal axis L. The switching element 12 is moved in the distaldirection when the cartridge holder 11 is rotated in a direction forreleasing the cartridge holder from the housing 4, 18. The switchingelement 12 is moved in the proximal direction when the cartridge holder11 is rotated in a direction for attaching the cartridge holder 11 tothe housing 4, 18. Particularly, the cartridge holder 11 can slip on theswitching element 12 if the cartridge holder 11 is rotated relative tothe housing 4, 18 and the switching element 12. The cartridge holder 11has on its proximal end, for example, an activation element 11 c havinga sloped surface that can slip on the switching element 12 when thecartridge holder 11 is rotated relative to the switching element 12thereby initiating the axial movement of the switching element 12.Preferably the switching element 12 has a recess 12 c, which is adaptedto the shape of the activation element 11 c, whereby the activationelement slips into recess 12 c upon insertion of the protrusion 11 binto the axial section of the bayonet slot 4 b. A subsequent rotation ofthe cartridge holder 11 relative to the switching element 12 releasesthe activation element from the recess 12 c whereby the switchingelement 12 moves along the longitudinal axis L. Rotation of thecartridge holder 11 in the opposite direction for removing the cartridgeholder 11 from the drive and dosing device establishes a form fitbetween the activation element 11 c and the recess 12 c whereby theswitching element is moved in the distal direction due to the resilientforces acting from the dose spring 5.

As mentioned previously, the coupling 70 is in its inactive state whenthe cartridge holder 11 is released from the drive and dosing device(see, e.g., FIG. 8). The piston rod 19 can be reset or pushed back intothe drive and dosing device, particularly through the muscle power ofthe user of the device. Hereby the piston rod 19 is rotationally securedwith respect to the housing 4, 18 and the piston rod 19 is moved axiallyalong the longitudinal axis L into the housing 4, 18. As a result, thestop element 20 is moved accordingly whereby the stop element 20 isrationally and axially secured with respect to the piston rod 19.Furthermore, the rotation member 13, 15 is rotated during reset in thefirst rotation direction because, as mentioned before, the coupling 70is in its inactive status.

The cartridge holder 11 can be attached to the drive and dosing deviceafter resetting the piston rod 19, as described above (see, e.g., FIG.9).

The drive and dosing device of FIGS. 1-10 b has a mechanism which,during dose dialing, particularly during dial up or dial down, producesan acoustic and/or tactile signal which also can be designated as a“click” and which dictates discrete angular steps for the dose knob 10when rotated with respect to the housing 4, 18. The mechanismencompasses particularly a dose adjustment ratchet 16, a ratchet ring 17and the drive sleeve 8. A first clicker surface 91 is located on anoutwardly projected ring-shaped collar of the drive sleeve 8 and thissurface, in this example a saw tooth structure, points in the distaldirection. The ratchet ring 17 has a second clicker surface 92 that isengaged with the first clicker surface 91 and which points in theproximal direction. Furthermore, the ratchet ring 17 has a third clickersurface 93 oriented towards the distal direction and which is engagedwith a fourth clicker surface 94 oriented towards the proximal directionand which is located at the dose adjustment ratchet 16. The clickersurfaces 91, 92, 93, 94 are saw tooth structures arranged on an outersurface of each component part. The individual saw tooth of the clickersurfaces are distanced over an angle corresponding to the discrete stepsdictated to the dose knob 10. For example, if for the drive and dosingdevice the dose shall be set in steps of 1 IU then the angular distancefor the saw tooth is adjusted such that rotation of the dose knob 10along one discrete step corresponds to 1 IU Accordingly, an acousticrespectively tactile signal is produced during each discrete step of therotation of the dose knob. For the sake of completeness, the angulardistance of the saw tooth can be such that it corresponds to angularsteps of the dose knob above or below 1 IU for example 0.5 IU or 2 IU or5 IU The dose adjustment ratchet 16 is rotationally secured and axiallymoveable along the longitudinal axis L in the housing 4, 18,particularly in the housing insert 4 if the dose button 21 is notactuated. When the dose button 21 is actuated, the dose adjustmentratchet 16 is moved along the longitudinal axis L out of this engagementso that the dose adjustment ratchet 16 is rotatable with respect to thehousing 4, 18. The dose adjustment ratchet 16 has external teeth 16 athat engage with internal teeth 4 d present at the inner surface of thehousing insert 4 that form a rotationally secure engagement. When thedose button 21 is pressed, the external teeth 16 a along thelongitudinal axis L are moved out of engagement from the internal teeth4 d, and the dose adjustment ratchet 16 is rotatable with respect to thehousing 4, 18. In other words the dose adjustment ratchet 16 isrotationally secured versus the housing 4, 18 during dose setting and isrotatable versus the housing 4, 18 during dose delivery.

The aforementioned mechanism in the shown embodiments also serves thepurpose of providing for the drive sleeve 8 a certain resistance againstrotation in the second direction during actuation of the dose button 21(e.g., when the dose button 21 is not in the actuated position yet) andthus preventing a premature rotation of the drive sleeve 8. Thisresistance against rotation is preferably (minimally) above the torquegenerated by the axial displacement of the actuation element 21, morespecifically the torque due to the threaded engagement between the dosesleeve 7 and the coupling sleeve 6 acting on the drive sleeve 8. Thisresistance against rotation disappears when the dose button 21 is beyondthe intermediate actuation position (described in more detail below).

Optionally, the unidirectional coupling 70 can provide a certainresistance against rotation in the second direction during actuation ofthe dose button 21 (e.g., the dose button 21 is not yet in the actuatedposition) thus preventing a premature rotation of the drive sleeve 8 inthe second direction, since the dispense coupling 81, 82 is alreadyclosed. If the dose button 21 is in its actuated position and pushed bythe user further in the distal direction, then the resistance providedby the unidirectional coupling is resolved, whereby the drive sleeve 8and the rotation member 13, 15 are rotated in the second direction.

The drive sleeve 8 is rotated relative to the dose adjustment ratchet 16upon dialing up a dose (e.g., rotation of the dose knob 10 is the firstdirection) and upon dialing down a dose (e.g., rotation of the dose knob10 in the second direction). The ratchet ring 17 is located between thefirst clicker surface 91 and the fourth clicker surface 94. Upon dialingup a dose, the ratchet ring 17 co-rotates relative to either the doseadjustment ratchet 16 or the drive sleeve 8, and does not co-rotaterelative to the other. During dialing down a dose, the ratchet ring 17does not co-rotate relative to either the dose adjustment ratchet 16 orthe drive sleeve 8 and co-rotates relative to the other. In the shownexample, the ratchet ring 17 follows the rotation of the drive sleeve 8during dial up and rotates relative to the dose adjustment ratchet 16.During down dialing of a dose, the dose sleeve 8 rotates relative to theratchet ring 17, whereby the ratchet ring 17 does not rotate relative tothe dose adjustment ratchet 16. During dialing up and dialing down theclicker surfaces 91 to 94 slide along each other and thus produce theso-called “clicks”. The dose spring 5 abuts with its proximal end thedose adjustment ratchet 16 and keeps the dose adjustment ratchet 16,ratchet ring 17 and the drive sleeve 8 in a ratchet engagement.Moreover, the dose spring 5 returns, as described, the dose button 21 toits original position. Upon actuation of the dose button 21, the doseadjustment ratchet 16, respectively the external teeth 16 a are movedout of the torque-proof engagement with the housing 4, 18, respectivelythe internal teeth 4 d, due to the distal movement of the drive sleeve 8and the ratchet ring 17, thus deactivating the clicker mechanism duringdose dispensing. It is preferred that the dispense coupling 81, 82 andthe coupling 16 a, 4 d are coupled during the movement of the dosebutton 21 (e.g., when the dose button is between the actuated and thenon-actuated position, such as in an intermediate position). Thisensures that—during the actuation of the dose button 21—the coupling 16a, 4 d is not decoupled until the dispense coupling 81, 82 is alreadycoupled. Thus it is ensured that no accidental shift of the set dose canoccur during the actuation of the dose button.

A second embodiment is shown in FIGS. 11-18 for a drive and dosingdevice with a sleeve shaped housing 4 which also acts as the mechanicholder. The housing 4 has a distal end to which a cartridge holder witha cartridge can be attached (not shown), and a proximal end having arotatable dose knob 10. The housing 4 has an internal thread whichengages an external thread of the scale drum 9, and the scale drum 9 isrotationally and axially stably connected to the dose knob 10. Althoughnot shown, the housing 4 has a region for viewing the dose scale, andthe scale drum 9 has a dose scale, such as one described in the firstembodiment. For setting a dose, the dose knob 10 is rotated in a firstdirection relative to the housing 4 out of the proximal end of thehousing 4. For correction of a dose and for dispensing a dose, the doseknob 10 is rotated in a second direction relative to the housing 4 intothe proximal end of the housing 4.

The drive and dosing device has a piston rod 19 with an externalthreading 19 a and at least a guide arranged parallel to thelongitudinal axis. The guide may be a guiding notch. A part of thehousing or a part rotationally locked to the housing engages with theguiding notch. The piston rod 19 may be rotationally fixed relative tothe housing 4 and moveable along the longitudinal axis L of the pistonrod 19, which is identical to the longitudinal axis L of the drive anddosing device. An internal thread of the nut 13 engages with theexternal thread of 19 a of the piston rod 19 whereby the nut 13 isaxially locked but rotatable connected to the housing 4. The piston rod19 has a distal end 19 b and a proximal end 19 c.

The rotation member 13 is rotationally-fixed connected to a drive sleeve8 via a reset coupling 73, 74, when the cartridge holder is connected tothe drive and dosing device. The reset coupling 73, 74 has a couplingstructure 74 shaped as teeth present at the external surface of therotating member 13. The drive sleeve 8 has the coupling structure 73which is shaped as teeth present at its internal surface. The rotatingmember 13 and the drive sleeve 8 are torque-proof connected if thecoupling structure 73 is coupled with the coupling structure 74. Thedrive sleeve 8 is rotationally locked and axially slidably connected tothe coupling sleeve 33 which surrounds the drive sleeve 8, for examplethrough protrusions present at the outer surface of the drive sleeve 8engaging with notches present at the inner surface of the couplingsleeve 33. The coupling sleeve 33 has, at its proximal end, an outwardlyprotruding collar having a first coupling structure 81, in the exampleshown as a plurality of teeth pointing into the distal direction. Thefirst coupling structure 81 is part of the dispense coupling 81, 82having also the second coupling structure 82 which is part of the doseknob 10 and/or the scale drum 9. The second coupling structure 82 has aplurality of teeth arranged on a circumferential surface. At theproximal end of the drive and dosing device is an actuation element 21shaped as a dose button that can be pressed in the distal directionrelative to the dose knob 10 to move along an actuation distance into anactuated position. A dose spring 5 is arranged between the couplingsleeve 33 and the dose button 21 which upon release of the dose button21 returns the dose button into the non-actuated position and which isstressed upon actuation of the dose button 21.

The drive sleeve 8 and the coupling sleeve 33 are rotationally lockedwith respect to the housing 4 during dose setting (e.g., dial up or dialdown of a dose). If the dose knob 10, as shown in FIGS. 12a-c , isrotated in a first direction for increasing a dose, then it is rotatedout of the proximal end of the housing 4 whereby the coupling structure82 of the dispense coupling 81, 82 slides along the coupling structure81 and whereby the coupling structure 81 and the coupling sleeve 33oscillate along the longitudinal axis L. The spring force of dose spring5 is selected such that it slightly presses the coupling structure 81into engagement with the second coupling structure 82 so that a rotationof the dose knob 10 presses the teeth of coupling structure 81 out ofengagement with the second coupling structure 82 without the couplingsleeve 33 following the rotation of the dose knob 10.

If the desired dose has been set (see, e.g., FIGS. 13a-13c ) then thedose button 21 is pressed (see, e.g., FIGS. 14a-14c ) and the couplingstructures 81, 82 are held in a rotationally-secure engagement throughthe actuation of the dose button 21 whereby the coupling sleeve 33follows the rotational movement of the dose knob 10 when the dose knob10 is rotated back into the housing (compare, e.g., FIGS. 13a-13c andFIGS. 14a-14c ). Generally speaking, the dose knob 10 is rotationallycoupled with nut 13 when the dose button 21 is actuated. This couplingmay be achieved through dispense coupling 81, 82, therotationally-secured connection between the coupling sleeve 33 and thedrive sleeve 8, and (at least temporarily, particularly when thecartridge holder has been attached to the device) therotationally-secured connection between the drive sleeve 8 and the nut13.

The piston rod 19 is displaced along a dispensing distance and is movedin the distal direction due to the rotation of the nut 13 in the seconddirection relative to the piston rod 19. The drive and dosing device ofthe second embodiment also has a mechanism to prevent setting a dosewhich is above the amount present in the cartridge. This mechanismcomprises a stop element 20 which surrounds the piston rod 19 in a ringshaped manner and which has an internal thread engaging with an externalthread of the piston rod 19. Particularly, the stop element 20 ispermanently rotationally-secured connected with the dose knob 10,preferably through coupling 31, 32. The coupling 31, 32 comprises afirst coupler sleeve 31 and a second coupler sleeve 32. The firstcoupling sleeve 31 and the second coupling sleeve 32 are interlockedsuch that they are rotationally secured and axially slidable withrespect to each other. The second coupling sleeve 32 follows the screwmovements of the dose knob 10 during dose setting and dose delivery. Thestop element 20 engages the first and/or second coupling sleeve 31, 32in a rotationally secure and axially slidable connection. The firstcoupling sleeve 31 and/or the second coupling sleeve 32 can have aguiding notch that engages a protrusion shaped at the outer surface ofthe stop element 20. The second coupling sleeve 32 is, with respect tothe dose knob 10, rotationally secured but axially moveable along theactuation distance of the dose button 21. For this, the second couplingsleeve 32 has at least one protrusion 32 a which engages a guideoriented parallel to the longitudinal axis L of the device. The dosespring 5 abuts the second coupler sleeve 32. Particularly, a flangeattached to the second coupling sleeve 32 is pressed against thecoupling sleeve 33, more preferably against its proximal end when thedose button 21 is activated whereby the coupling structures 81, 82 arein a rotational locked engagement.

The dose button 21 is preferably freely rotatable with respect to thedose knob 10 and/or second coupling sleeve 32. For this, the dose button21 can have a contact surface with a diameter as low as possible andwhich is disposed in the central area and which contacts a surface atthe proximal end of the coupler sleeve 32. This results in a reductionof the friction when there is a rotation between the coupling sleeve 32and the dose button 21.

If the dose knob 10 is rotated in the first rotation direction forincreasing a dose, then the stop element 20 is also rotated in the firstdirection relative to the piston rod 19, whereby the stop element 20 isscrewed along the piston rod 19 and relative to the housing 4 in thedistal direction towards the distal end 19 b. If the dose knob 10 isrotated in the second direction for reducing a dose, then the stopelement 20 is also rotated in the second direction relative to thepiston rod 19 whereby the stop element 20 is screwed along the pistonrod 19 and relative to the housing 4 in the proximal direction towardsthe proximal end 19 c.

If the dose button 21 is actuated for dispensing a dose, and the doseknob 10 is pushed back (and thereby screwed back) into the housing 4,then the stop element 20 will be screwed along the piston rod 19 towardsthe proximal end of the piston rod 19 whereby it, with respect to thehousing 4, rotates but remains axially at the same location. The reasonfor this is that the piston rod 19 moves into the dispensing direction.

At the end of the dose dispensing (see, e.g., FIGS. 14a-14c ), the stopelement 20 is located at the same position with respect to the pistonrod 19 as for the zero dose position before setting and dispensing adose. The kinematics of the stop element 20 may be the same as the firstembodiment.

Comparable to the first embodiment, the stop element 20 has at least onecatch 20 a, which is interacts with a stop limiter 15 a that is shapedon the nut 13.

In FIGS. 15a-15c , the situation is presented where the stop element 20prevents the setting of a dose that is above the amount present in thecartridge. The distance between the catch 20 a and the stop limiter 15 ais reduced when rotating the dose knob in the first rotation direction.The distance is proportional to the amount of product present in thecartridge. If the stop element 20 abuts the nut 13, then the rotation ofthe stop element 20 in the first rotation direction is prevented orblocked.

Also this embodiment can—comparable to the first embodiment—be modifiedsuch that the setting of a dose is prevented which would result in aremaining volume in the cartridge less than the residual volume of thenominal volume by reducing the distance between the stop limiter 15 aand the catch 20 a, for example during device assembly.

FIGS. 16a-16c shows the drive and dosing device after dispensing thedose which has been set in FIGS. 15a-15c . A rotation of the dose knob10 in the first rotation direction is not possible anymore.

Positioned between the nut 13 and the housing 4 is a unidirectionalcoupling 71, 72 (e.g., a ratchet) which in its active status tolerates arotation of the nut 13 relative to the piston rod 19 in the seconddirection only and which blocks a rotation in the first direction.Removing the cartridge or the cartridge holder from the drive and dosingdevice deactivates the unidirectional coupling 71, 72, particularly bydecoupling the coupling structures 73, 74 and/or coupling structures 71,72.

The unidirectional coupling 71, 72 has a first coupling structure 71which is established at a part of the housing 4, or at a part of anelement attached to the housing, here a ring-shaped element 75. Thesecond coupling structure 72 is disposed at the drive sleeve 8 andincludes at least one saw tooth, particularly pointing in the proximaldirection that, when it engages the first coupling structure 71, allowsonly a rotation of the drive sleeve 8 in the second direction but not inthe first rotation direction.

The cartridge or the cartridge holder (not shown) are connected with thedrive sleeve 8 such that the drive sleeve 8 is moved relative to thehousing 4 in the distal direction upon removing the cartridge from thedrive and dosing device and it is moved in the proximal directionrelative to the housing 4 upon fixation of the cartridge to the driveand dosing device. A switching element 12 is located between thecartridge holder and the drive sleeve 8 or between the cartridge and thedrive sleeve 8, which is actuated by the cartridge holder or thecartridge such that the switching element is moved along thelongitudinal axis L.

Switching element 12 and drive sleeve 8 are connected such that thedrive sleeve 8 follows the movements of the switching member 12 alongthe longitudinal axis L.

If the cartridge holder is removed from the drive and dosing device thenthe couplings 71, 72 and/or 73,74 are decoupled such that the nut 13 isrotatable in the first direction relative to the housing 4 (see, e.g.,FIGS. 17a-17c ). The piston rod 19 can be moved back into the drive anddosing device by applying a force in the proximal direction on thepiston rod 19 whereby the nut 13 rotates in the first direction relativeto the housing 4. The stop element 20 is taken along by the piston rod19 during the device resetting and the stop element 20 does not conductany movements relative to the piston rod 19.

A cartridge and/or a cartridge holder can be attached again to the driveand dosing device after the piston rod 19 has been completely reset(see, e.g., FIGS. 18a-18c ) whereby the switching element 12, and therewith the drive sleeve 8, is moved in the proximal direction relative tothe housing 4. As a consequence, the couplings 71, 72 respectively 73,74 are coupled so that a rotation of the nut 14 is only possible in thesecond direction but not in the first direction.

A third embodiment is shown in FIGS. 19-30 for a drive and dose settingmechanism with a housing 4, 18 including an external housing 18 and ahousing insert or mechanic holder 4. An exploded view is presented inFIG. 19, a cross section in FIG. 20 and a detail in FIG. 21, all for thedevice in its initial state. The mechanic holder 4 or housing insert isfixed (e.g., rotationally and axially fixed) with respect to theexternal housing 18. The housing insert 4 has an external thread 4 athat engages an internal thread 9 c of the scale drum 9 such that thescale drum 9 can be screwed along the longitudinal axis L of the housing4, 18. At the proximal end of the scale drum is located the dose knob 10and between the dose knob 10 and the scale drum 9 is an overload clutch45. The overload clutch 45 is designed as a hollow cylinder withexternal teeth 45 a located at the proximal end and a connector cut-out45 b at its distal end. The overload clutch is axially and rotationallysecured with respect to the scale drum 9 for example by a snap fitconnection, glued or welded together thereby using the cut out 45 b forsecuring the anchorage. The dose knob 10 has a rim 10 c that isconcentrically arranged around the proximal end of the overload clutch45 and internal teeth 10 d located on the inside of the rim 10 c suchthat the teeth 10 d engage the teeth 45 a located at the proximal end ofthe overload clutch 45. The teeth 10 d, 45 a are arranged parallel tothe longitudinal axis L of the drive and dosing mechanism and allow forrelative axial movement and are rotationally secured up to a thresholdtorque value when the meshing teeth start to ratchet. A dose knob cover10 f surrounds the dose knob 10 and the two parts are rotationally andaxially locked together and can be considered to mechanically behave asa single part. On the outside of the dose knob cover 10 f is a gripsurface 10 g, which is used to rotate the dose knob 10 with respect tothe housing 4, 18. The rotation of the dose knob 10 is transmitted tothe scale drum 9 via the overload clutch 45. The set dose will beincreased upon rotation of the dose knob 10 in the first direction andthe set dose will be decreased upon rotation in the second directionwhich is opposite to the first direction. Rotation of the dose knob 10in the first direction ensures that the scale drum is screwed out of theproximal end of the housing (see, e.g., FIG. 22) and rotation in thesecond direction moves the scale drum back into the housing 4, 18. Theoverload clutch mechanism 45 a, 10 d can be activated when the userwants to set a dose which exceeds the amount of product present in thecartridge. The stop element 20 is in the stop position and theengagement of the catch 20 a and stop limiter 15 a prevents rotation ofthe scale drum 9 in the first direction for increasing the dose (see,e.g., FIG. 26). If the user nevertheless tries to increase the dose, theratchet coupling 45 a, 10 d is activated and the meshing teeth canratchet therewith preventing that an excessive torque is transmittedfrom the dose knob 10 to the scale drum and finally to the stop limiter.The members 45 a and/or 10 d of the ratchet coupling are present onresilient arms or members that enable movement in the radial directionto ensure the ratchet functionality. The resilient arms are not shown inFIG. 19, 20 or 25. The overload protection can be a unidirectionalcoupling or a bidirectional coupling. The overload protection can alsobe activated for setting an individual dose when the amount of productpresent in the cartridge is sufficient and the scale drum is in themaximum dose position and the user tries to rotate the dose knob in thefirst direction or when the scale drum is in the zero dose position andthe user attempts to rotate the dose knob in the second rotationdirection.

The pen according to the third embodiment features a pen cap 1 with aclip 1 a. The external housing 18 has a display or viewing window 18 afor viewing the set dose on the scale drum 9 (see, e.g., FIG. 19). Thescale drum has the dose values printed on the outer surface. The dosevalues are consecutively arranged along a helix-shaped curve. Thearrangement on the outside of the scale drum and the interaction withthe viewing window while rotating the dose knob may be the same as thefirst embodiment described above. In the third embodiment, the dose knoband actuation functionalities are combined. Thus for setting a dose, thedose knob 10 is rotated and therewith also the scale drum 9 is rotatedwith respect to the housing due to the threaded engagement 4 a, 9 cbetween the housing insert 4 and the scale drum 9, and/or the matchingthread connection 7 b/6 b between the dose sleeve 7 and the clutch 6,respectively. The dose knob also functions as an actuation element whichcan be displaced in the distal direction along the actuation distancerelative to the scale drum 9 (compare, e.g., FIGS. 22 and 23). Theratchet coupling 45 a, 10 d transmits rotational forces up to athreshold value and allows for axial movement between the dose knob 10and the overload clutch 45. When the user pushes the dose knob 10 in thedistal direction, the dose knob moves over the actuation distancetowards the scale drum against the resilient force of the reset spring40 and thereby decoupling the ratchet coupling 45 a, 10 d, which allowsfor relative rotational movement between the scale drum and the doseknob (see, e.g., detailed cross sections in FIGS. 25a and 25b ). Uponreleasing the dose knob 10, the dose knob moves in the proximaldirection due to the reset spring 40 from the actuated into thenon-actuated position. The dose knob 10 can be depressed with the thumbfrom the non-actuated into the actuated position and upon furtherpressing, when the scale drum starts to rotate due to the threadedengagement with the housing insert 4, the dose knob moves towards therearward end of the device. The dose knob 10, which is in contact withthe users thumb, is not rotating whereas the scale drum rotates. In thefirst embodiment having a separate dose button and a dose knob, the userthat grabs the housing and pushes the dose button and the scale drumback into the housing (whereby the dose knob rotates versus anon-rotating dose button) has the potential for a brake drum effectwhere the thumb pushing the dose button potentially frictionally affectsthe rotation of the dose knob. By combining the two functionalities inthe dose knob of the third embodiment, the brake drum effect can beavoided.

For dispensing the set dose, the dose knob 10 is pressed further in thedistal direction such that the dose knob 10 moves in the distaldirection and the dose scale 9 rotates and is screwed back into thehousing 4, 18. FIG. 24 shows the embodiment after the dose set in FIG.22 is dispensed.

The location of the cartridge and cartridge holder 11 may be the same asin the first embodiment. The cartridge 11 a has a septum at its distalend which can be pierced by a needle for dispensing a product. Thecartridge also has a plug which can be moved in the distal direction fordispensing the liquid product present between the plug and the septum.The plug of the cartridge is operatively coupled to the piston rod 19and the piston rod 19 has a multiple threading 19 a on the outside whichengages an internal threading 13 a of the rotating member 13, 15. Therotating member of the third embodiment includes two parts, a threadednut or drive nut 13 and a drive nut socket 15 which are axially androtationally connected to each other. Between the nut 13 and the drivenut socket 15 is a circumferential notch which engages the bearing disc42 (see, e.g., FIG. 21). The bearing disc 42 is axially and rotationallysecured to the housing 18 by the arms 42 b that engage with matchingunits on the inside of the housing insert 4 in a snap-fit connection.Therewith the rotation member 13, 15 is axially locked, but rotationallyfree with respect to the housing 4, 18 and axial forces acting on therotation member 13, 15 are guided to the housing 4, 18 via the bearingdisc 42.

The functioning of the linear slide 2, which ensures that the piston rod19 can slide but not rotate with respect to the housing, is described indetail above. The guiding bushing 2 a of the linear slide 2 matches thelongitudinal notch 19 d of the piston rod 19 and, because the linearslide is rotationally secured with respect to the housing, ensures thatthe piston rod 19 can slide but not rotate with respect to the housing4, 18.

During dose setting, the rotating member 13, 15 is rotationally securedwith respect to the piston rod 19 (e.g., does not rotate with respect tothe piston rod 19). During dose delivery, the rotation member is rotatedrelative to the piston rod 19 and/or the housing 4, 18, preferably inthe second rotation direction. The rotation member 13, 15 follows, uponactuation of the dose knob 10, the rotation of the scale drum 9 and/ordose sleeve 7 during dose delivery. The rotation member 13, 15 engageswith the internal thread 13 a the external thread 19 a of the pistonrod. Since the piston rod 19 is axially guided by the bushing 2 a, thepiston rod will translate in the distal direction for dispensing the setdose. As mentioned above, the rotation member 13, 15 includes two partsthat are connected to each other and behave as a single part, howevereach part is optimized from a materials perspective to the specifictribological and/or mechanical needs. The threaded nut 13, may be madefrom, for example, Teflon, PTFE, a fluorocopolymer, with or withoutadditives to reduce the frictional losses. The drive nut socket 15 maybe made from a high strength polymer with or without fiberreinforcement.

Comparable to the first embodiment, a notch exists between the twocomponents of the rotation member 13, 15 and the notch engages a partthat is fixed to the housing (e.g., bearing disc 42). The notch of therotation member 13, 15 engages the bearing disc 42 and ensures that therotation member 13, 15 is rotatable but axially non-displaceable withrespect to the housing 4, 18.

The dispense coupling 81, 82 is closed upon depressing the combined doseknob 10 and is opened upon release of the dose knob 10. The dispensecoupling 81, 82 couples the rotation member 13, 15 torque-proof with thescale drum 9 and/or dose sleeve 7 and/or drive sleeve 8 when thedispense coupling 81, 82 is closed (as shown in FIGS. 22 and 23). Whenthe dose knob 10 is released, the coupling 81, 82 is opened and therotation member is rotationally decoupled from the dose sleeve 7 and/ordrive sleeve 8 and/or scale drum 9. Upon releasing the dose knob 10, thedose knob 10 moves in the proximal direction thereby the dose knob 10 iscoupled to the scale drum via the overload clutch coupling 45 a, 10 d.

The dispense coupling 81, 82 includes two coupling structures 81 and 82respectively that are described in more detail above for the firstembodiment. The two coupling structures are brought in a rotationallysecured engagement when the coupling is closed. The coupling structure81, 82 comprises a reset spring 40 which spring force tends to disengagethe first coupling structure 81 from the second coupling structure 82.The dispense coupling 81, 82 is closed upon actuation of the combineddose knob 10 thereby compressing the reset spring 40.

The reset spring 40 also serves the purpose of resetting the dose knob10 from the actuated into the non-actuated position, thereby closing thecoupling 45 a, 10 d

In the third embodiment, the first and second coupling structures 81 and82 include circumferentially arranged teeth oriented along thelongitudinal axis L of the device, comparable to the first example. Theteeth of the structures are configured such that they can axially slideover each other and interlock to form a torque-proof connection. Thesecond coupling structure 82 is rotationally connected to, preferablypart of the rotation member 13, 15, more preferably part of the drivenut socket 15.

Comparable to the first example, the first coupling structure 81 ispresent at the distal end of the drive sleeve 8 and the drive sleeve 8is kinematically or geometrically arranged between the dose knob 10 andthe rotation member 13, 15. The drive sleeve 8 is moved in the distaldirection with respect to the housing 4, 18 when the dose knob 10 ismoved in the distal direction during actuation from the non-actuated tothe actuated position. Upon release of the dose knob 10, the drivesleeve 8 will be displaced in the proximal direction via the resetspring 40 thus decoupling the coupling 81, 82. A disc 41 is locatedbetween the coupling structure 81 and the proximal end of the drivesleeve 8 and the disc 41 is axially locked but rotatable with respect tothe drive sleeve 8. The distal surface of the disc 41 abuts the proximalend of the reset spring 40 and energy stored in the reset spring 40 isreleased when the dose knob 10 moves from the actuated to thenon-actuated position thus moving the drive sleeve 8 in the proximaldirection via the disc 41.

Between the drive sleeve 8 and the dose knob 10 is a dose sleeve 7. Thedose sleeve may be rotationally secured but axially slidable withrespect to the drive sleeve 8 due to a key-cam interaction includinglongitudinal grooves and/or protrusions present between the dose sleeve7 and the drive sleeve 8; details are described above in the firstembodiment.

The dose sleeve 7 has a threading 7 b on the outside surface and theends of the thread provide for the stop zero dose and stop maximum dose,respectively. The coupling sleeve 6 is located between the housing 4, 18and the dose sleeve 7 having an internal thread 6 b that engages theouter thread 7 b of the dose sleeve 7. The thread ends interact with theinternal thread 6 b, or internal thread segment 6 b, to form the stopmaximum dose or stop zero dose arresters, comparable to the firstembodiment.

The dose sleeve 7 in the third embodiment is axially fixed with respectto the dose knob 10 both during dose setting and dose dispensing. Thebottom surface 10 e of dose knob cover 10 f touches the proximal endsurface 7 f of the dose sleeve 7 to transmit the axial forces (see,e.g., FIG. 20). During dose setting, the dose knob 10 is axially androtationally locked with respect to the dose sleeve 7. During dosedelivery, the dose sleeve 7 is axially coupled but rotationallydecoupled from the dose knob 10. During dose delivery, the dose sleeve 7rotates in the second direction whereas the dose knob 10 does notrotate. The contact surface between end surface 7 f and bottom surface10 e is shaped such to minimize the frictional losses during dosedelivery. In the third embodiment, the bottom surface 10 e has aprotrusion that engages a recess at the distal end surface 7 f (see,e.g., FIGS. 25a and 25b ).

Between the housing 4, 18 and the dose sleeve 7 is the coupling sleeve 6which is engaged with the housing 4, 18 such that the coupling sleeve 6is rotationally secured but axially slidable with respect to the housing4, 18. The engagement is described above in the first example and is akey-groove interaction between the outside surface of the couplingsleeve 6 and the inside of the housing 4, 18. On the inside of thecoupling sleeve 6 is the internal thread 6 b that engages the outsidethread 7 b of the dose sleeve 7. Upon actuation of the dose knob 10, thecoupling sleeve 6 is moved in the distal direction due to the threadedengagement between the coupling sleeve 6 and the dose sleeve 7 (compare,e.g., FIGS. 22 and 23). The axial movement of the coupling sleeve 6 istransmitted to the drive sleeve 8 via the disc 41.

A unidirectional coupling 71, 72, 73, 74 is located in the housing 4, 18and is generally referenced to as coupling 70. During dose settingand/or delivery the unidirectional coupling 70 prevents a rotation ofthe rotation member 13, 15 in the first rotation direction relative tothe housing 13, 15 and/or piston rod 19 whereas it permits a rotation inthe second direction. The unidirectional coupling 70 can be shaped as aratchet. The unidirectional coupling essentially functions identical tothe first embodiment and prevents frictional forces during dose settingfrom being transmitted to the rotation member 13, 15 and/or prevent thepiston rod from moving in the proximal direction due to elastic forcesacting from the plug of the cartridge upon the piston rod 19.

The unidirectional coupling 70 can be designed as a permanent couplingfor a disposable pen or as a releasable coupling for a reusable pen(e.g., when an empty cartridge 11 a is replaced by a new and fullcartridge). During exchange of the cartridge 11 a it is preferred thatthe rotation member 13, 15 is allowed to rotate in the first rotationdirection relative to the housing 4, 18 such that the piston rod canmove in the proximal direction and can be reset in its originalposition.

The unidirectional coupling 70 has a first coupling structure 71 and asecond coupling structure 72, whereby the first and second couplingstructures form a ratchet allowing for relative rotation in onedirection only. The first coupling structure 71 is, comparable to thefirst embodiment, directly or indirectly secured with respect to thehousing 4, 18, or at least rotationally locked to the housing, forexample through bearing disc 42. The second coupling structure 72 can beformed by the rotation member 13, 15, preferably by drive nut socket 15,more preferably by a part that is rotationally, preferably permanentlyrotationally connected to the rotation member 13, 15. In the thirdembodiment, the coupling structure 72 is preferably shaped onto couplingring 14 (see, e.g., FIG. 29a ). The coupling ring is preferablyrotationally locked and axially moveable with respect to the rotationmember 13, 15, during dose setting, dose dispensing and resetting of thedevice. The first and second coupling structures 71, 72 are engaged by aspring, preferably dose spring 5. The dose spring 5 serves the purposeonly for engaging the first and second coupling structures 71, 72 and isnot also used for resetting the dose knob 10 or for generating theclicks during dose setting or for moving into—or out of—the reset modefor exchanging a cartridge. The dose spring 5 is optimized, preferablyfor the sole purpose of the engagement of the first and second couplingstructures 71, 72. Preferably, the first and the second couplingstructures 71, 72 encompass circumferentially arranged saw toothstructures. The teeth of the two coupling structures preferably point toeach other. The teeth of the first structure 71 preferably point in theproximal direction and the teeth of the second structure 72 preferablypoint in the distal direction. The saw tooth structures 71, 72 have asteep and flat face which are pressed together by the dose spring 5. Thesaw tooth structures are arranged such that rotation of the second sawtooth structure 72 in the first direction relative to the first couplingstructure 71 is prevented. Thereby rotation of the coupling ring 14 inthe first direction is prevented and therewith also the rotation in thefirst direction of the rotation member 13, 15 due to the engagement ofthe third coupling structure 73 and the fourth coupling structure 74.The third coupling structure 73 includes internal teeth on the couplingring 14 that engage with external teeth of the fourth coupling structure74 present on the outside of the rotating member 13, 15. The couplingstructures 73 and 74 are arranged such that axial displacement betweenthe two members is allowed whereas rotational movements are prevented.

For setting a dose, the user rotates the dose knob cover 10 f andtherewith the dose knob 10 which is rotationally locked to the dose knobcover 10 f. The user rotates the dose knob 10 in the first direction andthe dose knob 10 is rotated out of the proximal end of the housing 4, 18together with the scale drum 9 (FIG. 22). The set dose can be read fromthe dose scale 9 b through the viewing window 18 a of the housing 18.The dispense coupling 81, 82 is decoupled.

For dispensing a set dose, the dose knob 10 is pressed in the distaldirection versus the scale drum 9 and/or housing 4, 18 along anactuation distance (see, e.g., FIG. 23). Thereby the overload coupling45 a, 10 d is decoupled, which rotationally decouples the dose knob 10from the scale drum 9 (see, e.g., FIGS. 25a and 25b ). The dose sleeve 7is also displaced versus the housing 4, 18 along the actuation distanceof the dose knob 10. The coupling sleeve 6 is also displaced in thedistal direction over the same actuation distance, this due to thethreaded engagement 7 b, 6 b that exists between the dose sleeve 7 andthe coupling sleeve (or clutch) 6. The coupling sleeve 6 pushes thedrive sleeve 8 in the distal direction over the actuation distance ofthe dose knob 10 via the disc 41 which is axially locked to the drivesleeve 8. The dose spring 5 is compressed over the actuation distanceand the first coupling structure 81 present at the drive sleeve 8 iscoupled to the second coupling structure 82 present at the rotationmember 13, 15 thereby forming a torque-proof engagement.

Upon further pressing the dose knob 10 in the distal direction, the doseknob is screwed back into the housing 4, 18 along a distancecorresponding to the set dose (FIG. 24). Hereby the scale drum 9 rotatesin the second direction due to the non-self-locking thread connection 4a/9 c and/or 7 b/6 b, whereas the dose knob does not rotate since thedose knob 10 is rotationally decoupled from the scale drum 9. The setdose value at the dose scale 9 b counts back as the scale drum 9 rotatesback into the housing and the rotational movement (e.g., torque in thesecond direction is transferred to the dose sleeve 7, the drive sleeve 8and finally to the rotation member 13, 15 via the coupling 81, 82). Therotation of the rotation member 13, 15 in the second direction istranslated into an axial movement of the piston rod 19 in the distaldirection whereby the piston rod 19 slides though the linear slide 2.The flange 19 b at the distal end of the piston rod 19 pushes againstthe plug of the cartridge for dispensing the set dose. The piston rod 19moves along the longitudinal axis L over a dispensing distance and thedose knob 10 moves along a dose setting distance whereby the dosesetting distance is above the dispensing distance. The differences indose setting distances and dispensing distances are governed bydifferent pitches of the threads of the scale drum (or dose sleeve) andpiston rod, respectively. The different pitches result in a gearing fromthe force applied to the dose button to the plug of the cartridge.

The device of the third embodiment has a stop element 20 comparable tothe first embodiment which prevents setting a dose that exceeds thedispensable volume present in the cartridge 11 a. The stop element 20 isa nut with internal thread 20 which rotates along the piston rod 19during dose setting and correction and which returns to its originalposition with respect to the piston rod during dose dispensing (see,e.g., FIGS. 26 and 27). Thereby the distance between the catch 20 a ofthe stop nut and the stop limiter 15 a of the rotation member 13, 15decreases upon repeated dose setting and dispensing. When the stop nut20 is in the stopping position (e.g., when the catch 20 a abuts the stoplimiter 15 a) the setting of a dose is prevented which exceeds theamount present in the cartridge 11 a. The functioning of the stopelement 20 of the third embodiment may be identical to the firstembodiment and is described in more detail above (see, e.g., FIGS. 6 and7 of the first embodiment).

The cartridge holder 11 holding the cartridge can be the same as thecartridge holder 11 of the first embodiment. The cartridge holder 11 maybe releasable from a drive and dosing mechanism that is intended for areusable injection device and the connector between the drive and dosingmechanism and the cartridge holder can be a bayonet type of connector(see, e.g., FIG. 28). The protrusion 11 b of the cartridge holder 11 isfirst axially inserted into the axial section of the bayonet slot 4 band subsequently locked into the circumferential section of the bayonetslot 4 b by rotation of the cartridge holder 11 and/or the housing 4,18. The functioning for closing and opening of the bayonet connector isidentical to the first embodiment described previously.

The cartridge that is inserted into the cartridge holder 11 is subjectedto dimensional tolerances, particularly with respect to the length ofthe cartridge (cartridge not shown in FIGS. 19-29 of the thirdembodiment). The device has a cartridge spring 3 which is presentbetween the cartridge and the bearing disc 42. The bearing disc 42 isaxially locked to the housing 4, 18 and, upon insertion of a newcartridge in the cartridge holder 11 and attachment to the housing, thecartridge is sandwiched between the distal end of the cartridge holderand the cartridge spring 3. The latter is compressed thus fixing thecartridge and compensating for tolerances in the length of thecartridge.

For the insertion of a new cartridge in a reusable device, the pistonrod 19 may be reset to its original position. For that, the piston rodmay be enabled to slide back into the drive and dosing mechanism and, asa result, the rotation member may rotate in the first rotationdirection. This rotation is prevented during dose setting and dosedelivery by the unidirectional coupling 70 and therefore this couplingmay be switched into an inactive state during reset of the piston rod19. For this, the first coupling structure 71 is decoupled from thesecond coupling structure 72 when the cartridge holder is removed fromthe housing 4, 18. During normal operation and during reset, the thirdand fourth coupling structures 73, 74 remain engaged in the thirdembodiment (see, e.g., FIG. 29a ). The cartridge holder 11 is coupledsuch to the first coupling structure 71 that the first couplingstructure 71 disengages from the second coupling structure 72 when thecartridge holder 11 is released from the drive and dosing device,particularly when the cartridge holder 11 is moved in the distaldirection relative to the housing 4, 18. The coupling 70 is than in itsinactive state (see, e.g., FIG. 29b ). On the reverse, when thecartridge holder 11 is attached to the drive, then the first couplingstructure 71 engages the second coupling structure 72, particularly, thefirst coupling structure 71 moves in the proximal direction therebyengaging the second coupling structure 72. The first coupling structure71, preferably present at the switching element 12 described below, canbe moved against the force of the reset spring 40 in the proximaldirection when attaching the cartridge holder. The coupling 70 is in theactive state. Upon releasing the cartridge holder from the drive anddosing mechanism, the first coupling structure 71 moves in the distaldirection due to the resilient forces of the reset spring 40.

The first coupling structure 71 is preferably present at the switchingelement 12 and the switching element 12 is axially slidable butrotationally secured with respect to the housing 4, 18 and thus can movealong the longitudinal axis L of the drive and dosing mechanism. In thethird embodiment, the switching element 12 is coupled such with thecartridge holder 11 that the switching element 12 moves in the proximaldirection when a new cartridge has been inserted and the bayonetconnection between the cartridge holder 11 and the housing 4, 18 isclosed (compare FIGS. 29a and 29b ). The switching element 12 moves inthe distal direction when the cartridge holder 11 is rotated withrespect to the housing 4, 18 for releasing the bayonet connection. Theswitching element 12 has protrusions 12 d that engage a slopedactivation surface 11 c at the proximal end of the cartridge holder 11.Inserting the cartridge holder 11 into the housing 4, 18 followed by arotation with respect to the housing for closing the bayonet connectorensures that the sloped surface of the cartridge pushes the switchingelement 12 in the proximal direction via the protrusions 12 d. When thebayonet connector is closed (e.g., when the protrusion 11 b of thecartridge holder 11 rests in the circumferential end of the bayonet slot4 b) the protrusion 12 d of the switching element will rest in a recesspresent at the end of the activation surface 11 c. The engagement of theelements lie and 12 d can be accompanied by a tactile and/or audiblesignal. The switching element 12 is biased by the reset spring 40 eitherdirectly or more preferably via an intermediate sleeve, preferably theratchet ring 17. Upon releasing the cartridge holder 11 from the driveand dosing mechanism, the switching element 12 is moved in the distaldirection by the spring forces acting from the reset spring 40.

The coupling 70 is in its inactive state when the cartridge holder 11 isreleased from the drive and dosing device. The piston rod 19 can bereset and pushed back into the drive and dosing mechanism since therotation of the rotation member 13, 15 in the first direction withrespect to the housing is allowed provided that the coupling 70 is nonactive. The piston rod is rotationally secured with respect to thehousing 4, 18 via linear slide 2 and the piston rod 19 slides back intothe housing without rotating. The stop element 20 is also moved in theproximal direction, as mentioned above for the first embodiment.

The automatic reset-retraction of the piston rod and/or automaticadvancement of the piston rod during exchange of a cartridge is notshown in the drawings and is described hereafter. For the automaticadvancement of the piston rod after exchange of a cartridge, the pistonrod 19 advances in the distal direction when the cartridge holder andcartridge have been removed from the housing. For example a compressionspring can be present between the distal end of the piston rod, forexample the flange 19 b, and the linear slide 2 or housing insert 4.After insertion of a new cartridge in the cartridge holder 11 andattachment of the cartridge holder to the drive and dosing mechanism,the plug of the cartridge pushes the piston rod in the proximaldirection against the resilient forces of the spring and afterattachment closure of the bayonet connection between the cartridgeholder 11 and the housing 4, 18, the flange 19 b of the piston rod abutsthe proximal end of the plug of the cartridge therewith avoiding theneed for a priming operation to close the gap between the piston rod andthe cartridge plug. Other variations of the concepts can be introducedsuch as for example, a spiral spring present between the rotation member13, 15 and the housing 4, 18. The spring energy stored facilitates arotation of the rotation member 13, 15 in the second direction when thecoupling 70 is decoupled (e.g., when the cartridge holder has beenremoved from the drive and dosing mechanism). Even if the piston rod isnot in the most distal position, either the compressive spring forcesmentioned before or the spiral spring forces acting on the rotationmember 13, 15 will advance the piston rod to the most distal position.During insertion of a new cartridge, the rotation of the rotation member13, 15 in the first direction required to reset the piston rod 19 willtension the spiral spring and a contact between the flange 19 b of thepiston rod 19 and the plug of the cartridge is guaranteed after thereset operation before setting and dispensing a dose from the newcartridge. For the automatic retraction of the piston rod during thereset operation a spiral spring can be, for example, present between therotation member 13, 15 and the housing 4, 18 and the spiral spring istensioned during repeated setting and dispensing of doses (e.g. duringadvancement of the piston rod). The energy stored in the spiral springpromotes a rotation of the rotation member 13, 15 in the firstdirection, thus when the coupling 70 is decoupled during reset of thedevice, the rotation member 13, 15 is rotated in the first direction andresults in a retraction of the piston rod prior to insertion of a newcartridge. As an alternative, a spring can be present and attached tothe piston rod 19 and the housing 4, 18. Such a spring is tensionedduring advancement of the piston rod (e.g., repeated dispensing of dosesand energy stored in the tension spring is released during reset of thedevice resulting in an automatic retraction of the piston rod 19).

The drive and dosing device according to the third embodiment has amechanism which during dose dialing (e.g. dial up or dial down) producesacoustic and/or tactile signals that can be designated as clicks andwhich dictate discrete angular steps to the dose knob 10 during dosedialing and which correspond to the International Units (IU) set and/orcorrected (see, e.g., FIGS. 19 and 21). The mechanism comprises a sleeveshaped ratchet ring 17 which is concentrically arranged around thedistal end of the drive sleeve 8. Protrusions 8 b on the outside of thedrive sleeve 8 engage grooves 17 a present on the inside of the ratchetring 17 to form a rotationally secure connection during dose setting.The ratchet ring 17 has a first clicker surface 91 circumferentiallyarranged at the distal end of the ratchet ring 17 and includes a toothstructure with the teeth pointing in the distal direction. The teethhave two sloped surfaces and the sloped surface of each side of a singletooth can be inclined differently, but preferably the slopes are equal(e.g., resulting in symmetrically shaped teeth). The ratchet ring 17 isbiased by the dose spring 40 which on its distal end abuts the proximalend of the ratchet ring 17 and on its proximal end touches the disc 41that is axially fixed to the drive sleeve 8. The second clicker surface92 is located at the switching element 12 and comprises a toothstructure circumferentially arranged on the proximal surface of theswitching element 12 with the teeth pointing in the proximal direction.The second clicker surface 92 has preferably complementary teeth to thefirst clicker surface that can ratchet with the teeth of the firstclicker surface 91. The second clicker surface 92 is rotationally andaxially secure connected to the switching element 12 which itself isrotationally secured with respect to the housing (e.g., the secondclicker surface 92 is rotationally secured with respect to the housing4, 18). During dose setting, the dose knob 10 is rotated for setting aparticular dose and the scale drum 9 and dose sleeve 7 are rotated outof the housing 4, 18. The drive sleeve 8 is rotated due to the key-camengagement 7 c, 8 c and with the drive sleeve 8 also the ratchet ring 17will rotate because of the engagement between protrusion 8 b and grooves17 a. The first clicker surface 91 of the rotating ratchet ring 17 willratchet against the second clicker 92 of the non-rotating switchingelement 12 under the resilient forces of the reset spring 40. Theratchet ring 17 will ratchet versus the switching element 12. Theindividual tooth of the first and second clickers surfaces 91, 92 arespaced apart such that each step corresponds to 1 IU (e.g., each clickof the ratchet system during dial up or dial down of a dose correspondsto 1 IU). When the dose knob 10 is actuated and moved from thenon-actuated to the actuated position, the drive sleeve 8 is also movedin the distal direction with respect to the housing over the actuationdistance thereby bringing the coupling 81, 82 into engagement. Beforethe engagement of the coupling 81, 82 it is preferred to disengage thecoupling 8 b, 17 a between the dose sleeve 8 and the ratchet ring 17,the reverse (e.g. first closing the coupling 81, 82 before decouplingthe coupling 8 b, 17 a) is a more preferred option.

During decoupling the coupling 8 b, 17 a, the protrusion 8 b is broughtout of engagement with the grooves 17 a. Thus the ratchet system forgenerating the clicks is non-active once the dose knob 10 has beenactuated.

During actuation of the dose knob 10, a torque in the second directioncan be generated in the drive train, more specifically the torque due tothe threaded engagement between the dose sleeve 7 and the couplingsleeve 6 and/or the housing insert 4 and the scale drum 9. This torqueduring actuation (e.g. during movement from the non-actuated to theactuated position) could result in an undesirable rotation in the seconddirection of the drive sleeve 8. This torque moment can be compensatedfor by the bidirectional ratchet coupling 91, 92 and/or theunidirectional coupling 71, 72. The latter is intended to prevent arotation in the first rotation direction by its asymmetric toothstructures but also has, although much lower, a resistance to rotationin the first direction which is needed for generating the clicks duringdose delivery, as will be described below.

Upon further pressing the dose knob 10 after having moved over theactuation distance, the dose knob 10 moves in the distal direction andthe scale drum 9, dose sleeve 7 and drive sleeve 8 co-rotate in thesecond rotation direction. The dispense coupling 81, 82 is closed andtherefore also the rotation member 13, 15 rotates in the second rotationdirection whereby the coupling ring 14 also rotates in the secondrotation direction due to the internal/external tooth connection 73, 74.The coupling ring 14 is biased by the dose spring 5 which is locatedbetween the drive nut socket 15 of the rotation member 13, 15 and theproximal surface of the coupling ring 14. The distal surface of thecoupling ring 14 comprises the second coupling structure 72, shaped as asaw tooth structure that engages the first coupling structure 71 presentat the switching element 12. The two saw tooth structures are pushedinto engagement by the dose spring 5 thereby forming the unidirectionalcoupling 71, 72 that prevents rotation of the rotation member 13, 15 inthe first rotation direction. When the rotation member 13, 15 rotates inthe second rotation direction during dose dispensing, the saw tooth ofthe coupling structures 71, 72 ratchet over each other thereby producingthe audible and/or tactile clicks during dose delivery.

During reset of the drive and dosing mechanism, the cartridge holder 11is removed and the switching element 12 moves in the distal directiondue to the spring force of reset spring 40 and thereby the firstcoupling structure 71 disengages from the second coupling structure 72.

The second coupling structure 72 is located at the coupling ring 14which itself is biased by dose spring 5. When the cartridge holder isremoved, the coupling 71, 72 is decoupled due to the distal movement ofthe switching element 12. The distal movement of the coupling ring 14 isrestricted by the bearing disc 42 and the coupling 71, 72 is decoupleddue to the distal movement of the switching element 12 (see, e.g., FIG.29). The coupling 73, 74 between the coupling ring 14 and the rotationmember 13, 15 remains in the coupled state during reset of the drive anddosing mechanism.

The drive and dosing mechanism of the third embodiment uses a separatedose spring 5 dedicated to the unidirectional coupling 71, 72 and aseparate reset spring 40 for the dose setting click mechanism 91, 92,the reset of the dose knob 10 to the non-actuated state and the distalmovement of the switching element 12 when the cartridge holder 11 isremoved, respectively. The drive and dosing mechanism of the firstembodiment uses one dose spring 5 for all four functionalities (see,e.g., FIG. 1). During dose delivery, a substantial amount of thefrictional losses is caused by the dispensing clicking mechanism andthose frictional losses are proportional to the normal forces governedby the separate dose spring of the third embodiment and the combineddose spring of the first embodiment, respectively. The force efficiency(E) of the drive and dosing mechanism is calculated as the ratio betweenthe forces acting on the plug of the ampoule (F_(out)) divided by theaxial forces applied to the dose knob 10 or dose button 21, (F_(in)).

The sum of the moments and forces of the drive and dosing mechanism canbe calculated with the following (generalized) formula:

F _(in) =F _(out) +ΣF _(Loss) i

The frictional losses can be calculated with:

F _(i)=/μ_(i) ×F _(i) ^(N)

The force efficiency E of the device is defined as:

$E = \frac{F_{out}}{F_{in}}$

Whereby μ_(i) is the specific frictional coefficient and F_(i) ^(N) thenormal force

For the first embodiment using one dose spring (defining the normalforce on several components):

F _(in) =F _(out) +F _(Loss) ^((scale drum9-housing insert4)) +F _(Loss)^((dose sleeve 7-clutch6)) +F _(Loss) ^((drive sleeve8-clutch6)) +F_(Loss) ^((dose sleeve7-drive sleeve8)) +F _(Loss)^((drive nut 13-piston rod19)) +F _(Loss)^((dose click disc 14-dose click ratchet 12)) +F _(Loss)^((piston rod 19-linear slide2))

The dose spring 5 in the first embodiment serves several purposes, suchas:

-   -   1) generating the resilient force needed for the clicks during        dose dispensing between the dose click disc 14 and the dose        click ratchet 12;    -   2) generating the resilient force needed for dose        setting/adjustment clicks between the dose adjustment ratchet 16        and the dose adjustment click disc 17 (dose setting) between the        dose adjustment click disc 17 and the drive sleeve 8 (dose        correction);    -   3) Reset from dose dispensing to the dose setting mode; and    -   4) Reset of the device during exchange of a cartridge.

The dose spring of the first embodiment is adjusted to the highest forceneeded of the 4 functionalities listed above and therefore producesnormal forces F_(n) between the drive sleeve 8 and the clutch 6 which,in combination with the unavoidable frictional coefficient existingbetween the two adjacent surfaces, lead to high frictional losses duringdose dispensing and therewith reducing the efficiency of the device.

For the third embodiment, one dose spring 5 and one reset spring 40 areused (defining the normal forces):

F _(in) =F _(out) +F _(Loss) ^((scale drum9-housing insert4)) +F _(Loss)^((dose sleeve 7-clutch6)) +F _(Loss) ^((drive sleeve8-clutch6)) +F_(Loss) ^((dose sleeve7-drive sleeve8)) +F _(Loss)^((drive nut 13-piston rod19)) +F _(Loss)^((coupling ring 14(72)-switching element 12(71))) +F _(Loss)^((piston rod 19-linear slide2))

The dose spring 5 in the third embodiment is adjusted to one specificneed only, generating the clicks using the unidirectional couplingelements 71 and 72 during dose dispensing. The spring forces needed forthe clicker functionality are lower. As a consequence, the normal forcesacting between the bearing surfaces of the click disc (coupling ring 14)are lower and therewith also the frictional losses which improves theefficiency of the driving mechanism.

The reset spring 40 is needed for:

-   -   1) generating the resilient force needed for dose        setting/adjustment clicks between the ratchet ring 17 (91) and        the switching element 12 (92) (dose setting and correction);    -   2) Reset from dose dispensing to the dose setting mode; and    -   3) Reset of the device during exchange of a cartridge.

Based on the above described model the device efficiencies have beencalculated using the following spring forces:

-   -   First embodiment—Dose spring 5 with a force ranging from 1 N to        4 N, preferably between 1.5 and 3 N, more preferably 2 N.    -   Third embodiment—Dose spring 5 with a force ranging between 0        and 1 N, preferably between 0.25 and 0.75 N, more preferably 0.5        N and a reset spring with a force ranging between 1 N and 3 N,        preferably 2 N.

The device force efficiencies (device output/user input force) have beencalculated for different maximum dose stroke (dose setting) settingdistances for the device according to the first embodiment (see FIG. 30a) and the third embodiment (see FIG. 30b ). The dose setting distance ordose stroke is defined as the maximum axial displacement that the doseknob can be rotated out of the proximal end of the housing 4, 18. Ahigher dose setting distances calls for a higher pitch of the thread 4a, 9 c between the housing insert 4 and the scale drum 9 (and thus alsoan equally higher pitch of the thread 7 b, 6 b between the dose sleeve 7and the clutch 6). A higher pitch of the dose setting members implies,at a constant pitch of the thread 19 a of the piston rod, also a highergearing ratio of the device. Due to the gearing ratio of the device itis possible to have a higher output force compared to the input force(device force efficiencies above 1).

The combination of the users requirements in terms of dose settingdistance (stroke length for the users thumb), force applied on the doseknob/dose button and desired device efficiency, defines a window foroptimum operation of the drive and dosing mechanism. The user's inputforce for operating the device is targeted at the range of 0 N to 10 Nand the stroke length for the thumb ranging between 25 mm and 33 mm. Ifdevice efficiencies above 1 are preferred, then this is feasible for thedrive and dosing mechanism according to the first embodiment with astroke length of 30 mm whereas 25 mm is sufficient for the thirdembodiment (see arrows in FIGS. 30a and 30b ). In other words, thereduction of the frictional losses due to an optimized clicker mechanismfor dose dispensing results in higher device efficiency for a certainstroke length and/or users input force.

What is claimed is:
 1. A drive and dosing device for an injection deviceconfigured for the attachment of a cartridge, the drive and dosingdevice comprising: a housing; a piston rod comprising a distal end and athread, the piston rod moveable in a dispensing direction with respectto the housing for dispensing a product; a rotation member engaged withthe thread of the piston rod and rotationally secured to a stop limiter,wherein the rotation member is engaged with the thread of the piston rodsuch that the rotation member causes the piston rod to move in thedispensing direction when the rotation member is rotated in a firstdirection relative to the piston rod; a dose knob rotatable in a dosesetting direction relative to the housing or the piston rod to increasea dose to be dispensed from the cartridge; and a stop element comprisinga catch, the stop element threadedly engaged with the thread of thepiston rod, wherein the dose knob is coupled with the stop element suchthat rotating the dose knob in the dose setting direction results inrotating the stop element relative to the piston rod, whereby the stopelement is moved towards the distal end of the piston rod and the catchis moved towards the stop limiter, and wherein the stop element preventsrotation of the dose knob in the dose setting direction when the catchabuts the stop limiter.
 2. The device according to claim 1, wherein thedose knob is rotatable in a direction opposite the dose settingdirection for decreasing the dose to be dispensed, and wherein rotationof the dose knob relative to the piston rod in the direction oppositethe dose setting direction causes the catch to move away from the stoplimiter and the stop element to rotate relative to the piston rod and bemoved towards a proximal end of the piston rod.
 3. The device accordingto claim 1, further comprising an actuation element, wherein uponactuating the actuation element, the actuation element is configured tocause the rotation member to rotate relative to the housing and thepiston rod such that the piston rod moves relative to the housing in thedispensing direction and the stop element is moved towards a proximalend of the piston rod.
 4. The device according to claim 3, wherein uponactuating the actuation element, a distance between the stop limiter andthe catch remains constant.
 5. The device according to claim 1, furthercomprising a unidirectional coupling between the housing and therotation member, the unidirectional coupling enabling the rotationmember to rotate in one direction such that the piston rod is moved inthe dispensing direction, and wherein the unidirectional couplingprevents a rotation in the direction opposite the dispensing direction.6. The device according to claim 5, wherein the unidirectional couplingis configured to be switched between an activated state and aninactivated state, wherein in the activated state, the unidirectionalcoupling permits a rotation of the rotation member in a rotationdirection which moves the piston rod in the dispensing direction andprevents rotation in a direction opposite the dispensing direction, andwherein in the inactivated state, the unidirectional coupling permits arotation of the rotation member in the direction opposite the dispensingdirection.
 7. The device according to claim 6, further comprising: acartridge holder configured to removably receive a cartridge and tocouple to the distal end of the housing; and a switching elementarranged between the cartridge holder and the unidirectional coupling,wherein the switching element is movable relative to the housing in theproximal direction upon coupling the cartridge holder to the housingthereby switching the unidirectional coupling to the activated state,and wherein the switching element is movable in the distal directionupon removing the cartridge holder thereby switching the unidirectionalcoupling to the inactivated state.
 8. The device of claim 6, wherein theengagement between the rotation member and the thread of the piston rodcomprises interlocking threading having a pitch configured to preventself-locking when the piston rod, with inactivated unidirectionalcoupling, is reset opposite to the dispensing direction, whereby therotation member rotates in the direction opposite the dispensingdirection.
 9. The device of claim 1, further comprising a scale drumrotationally coupled to the dose knob, the scale drum comprising ahelically-shaped scale, wherein the housing comprises a viewing windowconfigured to expose a portion of the helically-shaped scalecorresponding to the dose to be dispensed, and wherein the scale drum isconfigured to rotate relative to the housing upon rotation of the doseknob thereby causing a portion of the dose scale corresponding to thedose to be dispensed to be exposed.
 10. The device of claim 9, whereinthe scale drum is rotatable between a zero dose position and a maximumdose position, and wherein the scale drum comprises: a stop zero dose inthe zero dose position of the scale drum configured to prevent rotationof the scale drum in the direction opposite the dose setting directionand permit rotation in the dose setting direction, and a stop maximumdose in the maximum dose position of the scale drum configured toprevent rotation of the scale drum in the dose setting direction andpermit rotation in the direction opposite the dose setting direction.11. The drive and dosing device of claim 10, wherein the catch of thestop element is configured to abut the stop limiter when an increaseddose would exceed a dispensable amount of product present in thecartridge, thereby preventing rotation of the scale drum in the dosesetting direction.
 12. The drive and dosing device of claim 1, whereinthe stop element is coupled with the dose knob such that the stopelement is rotated along the piston rod during setting of the dose to bedispensed and during dispensing.
 13. The drive and dosing device ofclaim 1, further comprising: an actuation element configured to beactuated for dispensing the dose to be dispensed; and a dispensecoupling, wherein the dispense coupling is closed when the actuationelement is actuated and is opened when the actuation element isreleased, wherein the rotation member is rotationally coupled with thedose knob when the dispense coupling is closed, and wherein the rotationmember is rotatable with respect to the dose knob when the dispensecoupling is open.
 14. The drive and dosing device of claim 1, whereinthe stop element is rotationally coupled to the dose knob during dosesetting and during dispensing.
 15. The drive and dosing device of claim1, further comprising a sleeve kinematically positioned between the doseknob and the stop element, wherein the stop element is engaged with thesleeve such that the stop element is rotationally secure and axiallyslidable relative to the sleeve, and wherein the sleeve is coupled tothe dose knob such that the sleeve and the dose knob are rotationallysecure relative to each other.
 16. The drive and dosing device of claim1, wherein the stop element is in a position with respect to the pistonrod before a dose to be dispensed is set, and wherein the stop elementis in the position after dispensing the set dose to be dispensed.
 17. Aninjection device for dispensing a product, the injection devicecomprising: a housing; a cartridge containing a nominal volume of theproduct, wherein only a dispensable volume of the nominal volume can bedispensed with the injection device and a residual volume of the nominalvolume cannot be dispensed; a dose knob rotatable in a dose settingdirection relative to the housing to increase the dispensable dose androtatable in a direction opposite the dose setting direction relative tothe housing to decrease the dispensable dose; a stop limiter; and a stopelement coupled to the dose knob, wherein the stop element is configuredto move toward the stop limiter during a rotation of the dose knob inthe dose setting direction, and wherein a distance proportional to thedispensable volume and measured along a helix shaped curve is reduced,wherein the stop element is configured to remain stationary with respectto the stop limiter during dispensing of a set dose, and wherein whenthe stop element abuts the stop limiter, the setting of a dose isprevented, the dispensing of which would also dispense at least aportion of the residual volume or would result in less than the residualvolume of the nominal volume remaining in the cartridge.
 18. The deviceof claim 17, wherein the stop element is arranged with respect to thestop limiter along a distance, and wherein the distance is directlyproportional to the dispensable volume.
 19. The device of claim 18,wherein the distance along which the stop element is arranged withrespect to the stop limiter is measured along a helix shaped curve.